The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name Nusakan for the component Beta Coronae Borealis A on 12 September 2016 and it is now so included in the List of IAU- approved Star Names. In Chinese, (), meaning Coiled Thong, refers to an asterism consisting of Beta Coronae Borealis, Pi Coronae Borealis, Theta Coronae Borealis, Alpha Coronae Borealis, Gamma Coronae Borealis, Delta Coronae Borealis, Epsilon Coronae Borealis, Iota Coronae Borealis and Rho Coronae Borealis. 中國星座神話, written by 陳久金.
|
|
The term nayyir al-fakka or Nir al Feccah appeared in the Al Achsasi Al Mouakket catalogue. In Chinese, (), meaning Coiled Thong, refers to an asterism consisting of Alpha Coronae Borealis, Pi Coronae Borealis, Theta Coronae Borealis, Beta Coronae Borealis, Gamma Coronae Borealis, Delta Coronae Borealis, Epsilon Coronae Borealis, Iota Coronae Borealis and Rho Coronae Borealis. 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, .
|
|
The WGSN approved the name Meridiana for this star on 5 September 2017 and it is now so included in the List of IAU-approved Star Names. In Chinese, (), meaning River Turtle, refers to an asterism consisting of Alpha Coronae Australis, Alpha Telescopii, Eta¹ Coronae Australis, Zeta Coronae Australis, Delta Coronae Australis, Beta Coronae Australis, Gamma Coronae Australis, Epsilon Coronae Australis, HD 175362, Kappa² Coronae Australis and Theta Coronae Australis. 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, .
|
|
It was later referred to as Variabilis Coronae, "Variable (star) of Corona (Borealis)". It has also been called a "reverse nova" because of its habit of fading from sight. The variable star designation R Coronae Borealis was introduced, as "Coronae R" by Friedrich Wilhelm Argelander in 1850.
|
|
Light curve for the Mira variable S Coronae Borealis over six years S Coronae Borealis (S CrB) is a Mira variable star in the constellation Corona Borealis. Its apparent magnitude varies between 5.8 and 14.1, with a period of 360 days—just under a year. Within the constellation, it lies to the west of Theta Coronae Borealis, and around 1 degree southeast of the eclipsing binary star U Coronae Borealis.
|
|
Coronae Montes is a mountain on the planet Mars. The name Coronae Montesis a classical albedo name. It has a diameter of . This was approved by International Astronomical Union in 1991.
|
|
Theta Coronae Borealis, Latinized from θ Coronae Borealis, is a binary star system in the constellation Corona Borealis. It shines with a combined apparent visual magnitude (V band) of 4.13. There are two components: Theta Coronae Borealis A is of apparent magnitude 4.16, while Theta Coronae Borealis B lies around 1 arcsecond distant and has an apparent magnitude of 6.29. The system is located around 375 light-years from Earth, as estimated from its parallax of 8.69 milliarcseconds.
|
|
Alpha Coronae Australis (α Coronae Australis, abbreviated Alf CrA, α CrA), officially named Meridiana , is the brightest star in the constellation of Corona Australis and is located about 125 light-years from Earth.
|
|
In planetary geology, a corona (plural: coronae ) is an oval-shaped feature. Coronae appear on both the planet Venus and Uranus's moon Miranda and may be formed by upwellings of warm material below the surface.
|
|
The yellow supergiant R Coronae Borealis is the prototype of a rare class of giant stars—the R Coronae Borealis variables—that are extremely hydrogen deficient, and thought to result from the merger of two white dwarfs. T Coronae Borealis, also known as the Blaze Star, is another unusual type of variable star known as a recurrent nova. Normally of magnitude 10, it last flared up to magnitude 2 in 1946. ADS 9731 and Sigma Coronae Borealis are multiple star systems with six and five components respectively.
|
|
Light curve of R Coronae Borealis from 1990 to 2017, showing the unprecedented deep minimum The variability of R Coronae Borealis was discovered by English astronomer Edward Pigott in 1795. In 1935 it was the first star shown to have a different chemical composition to the Sun via spectral analysis. R Coronae Borealis is the prototype of the R Coronae Borealis class of variable stars. It is one of only two R Coronae Borealis variables bright enough to be seen with the naked eye, along with RY Sagittarii. Much of the time it shows variations of around a tenth of a magnitude with poorly defined periods that have been reported as 40 and 51 days.
|
|
Though named for a star in Boötes, the Phi Bootid radiant has moved into Hercules. The meteor stream is associated with three different asteroids: 1620 Geographos, 2062 Aten, and 1978 CA. The Lambda Bootids, part of the Bootid-Coronae Borealid Complex, are a weak annual shower with moderately fast meteors; 41.75 km/s. The complex includes the Lambda Bootids, as well as the Theta Coronae Borealids and Xi Coronae Borealids. All of the Bootid-Coronae Borealid showers are Jupiter family comet showers; the streams in the complex have highly inclined orbits.
|
|
Eta Coronae Borealis (η Coronae Borealis, η CrB) is a stellar system that lies approximately 58 light-years away. The primary component is a mid-wide binary, while a brown dwarf component is located at a wide separation.
|
|
WX Coronae Australis (WX CrA) is a star in the constellation Corona Australis.
|
|
The angular size of the object was estimated at 20 arcminutes. The object passed near the stars Gamma Geminorum, Eta Geminorum, Capella, 172 Camelopardalis, 50 Cassiopeiae, Gamma Cephei, Psi Draconis, 16 Draconis, Psi Herculis, Kappa Coronae Borealis and Delta Coronae Borealis. The object stopped near Gamma Cephei at an azimuth of 220°. Near Kappa Coronae Borealis, at an azimuth of 340°–350°, the object changed its direction to 30°–35° west.
|
|
Theta Coronae Australis, Latinized from θ Coronae Australis, is a star located in the constellation Corona Australis. Theta Coronae Australis is also known as HR 6951, and HD 170845. Parallax measurements by Hipparcos put it at a distance of roughly 560 light-years, or 171 parsecs, away from the Solar System. Theta Coronae Australis is a G-type giant star that is radiating 497 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,794 K. It has an apparent visual magnitude of 4.64, and is about 11 times wider than the Sun.
|
|
Coronae are large, circular structures with concentric fractures around them that result from mantle upwelling followed by extensional collapse. Since many sequences of upwelling and collapse have been observed as structurally different coronae on Venus' surface, all coronae appear to share a sequence of heavy volcanism as a result of upwelling, topographic rise, tectonic deformation, subsidence due to gravitational collapse, and continued volcanism. Coronae on Venus differ in the location of topographic uplift, and have been characterized as such. Topographic uplift may occur in the depression, the rim, the outer rim, or a combination of these locations.
|
|
Delta Coronae Borealis, Latinized from δ Coronae Borealis, is a variable star in the constellation Corona Borealis. Its apparent magnitude varies regularly between apparent magnitude 4.57 and 4.69, and it is around 170 light-years distant. δ Coronae Borealis is a yellow giant star of spectral type G3.5III that is around 2.4 times as massive as the Sun and has swollen to 7.4 times its radius. It has a surface temperature of 5180 K. For most of its existence, Delta Coronae Borealis was a blue-white main sequence star of spectral type B before it ran out of hydrogen fuel in its core.
|
|
A collapsing coronae coupled with extensional stressing may result in rifting, creating a chasmata region.
|
|
Asaphocrita coronae is a moth in the family Blastobasidae that is endemic to Costa Rica.
|
|
John Flamsteed did likewise with Nu Coronae Borealis; classed by Bayer as a single star, it was noted to be two close stars by Flamsteed. He named them 20 and 21 Coronae Borealis in his catalogue, alongside the designations Nu1 and Nu2 respectively. Chinese astronomers deemed nine stars to make up the asterism, adding Pi and Rho Coronae Borealis. Within the constellation's borders, there are 37 stars brighter than or equal to apparent magnitude 6.5.
|
|
V Coronae Australis (V CrA) is a R Coronae Borealis variable star in the constellation Corona Australis. These are extremely hydrogen-deficient supergiants thought to have arisen as the result of the merger of two white dwarfs; fewer than 100 have been discovered as of 2012. V Coronae Australis dimmed in brightness from 1994 to 1998. It has around 60% the mass of the Sun and an effective (surface) temperature of around 6250 K.
|
|
In 2006, a shower originating near Beta Coronae Australis was designated as the Beta Coronae Australids. They appear in May, the same month as a nearby shower known as the May Microscopids, but the two showers have different trajectories and are unlikely to be related.
|
|
R Coronae Borealis in optical light R Coronae Borealis is about 90% helium and less than 1% hydrogen. The majority of the remainder is carbon. This classifies it as a carbon-enhanced extreme helium star. Modelling the pulsations suggests that the star's mass is .
|
|
Rho Coronae Borealis (ρ CrB, ρ Coronae Borealis) is a yellow dwarf star approximately 57 light-years away in the constellation of Corona Borealis. The star is thought to be similar to the Sun with nearly the same mass, radius, and luminosity. It is orbited by two known exoplanets.
|
|
Alpha Coronae Borealis (α Coronae Borealis, abbreviated Alpha CrB, α CrB), officially named Alphecca , is an eclipsing binary star in the constellation of Corona Borealis. It is located about 75 light years from the Sun and contains two main sequence stars, one class A and one class G.
|
|
This has been calculated to be a planet around 6.7 times as massive as Jupiter orbiting at a distance of 1.3 astronomical units with an eccentricity of 0.11. Epsilon Coronae Borealis lies one degree north of (and is used as a guide for) the variable T Coronae Borealis.
|
|
The seven stars that make up the constellation's distinctive crown-shaped pattern are all 4th-magnitude stars except for the brightest of them, Alpha Coronae Borealis. The other six stars are Theta, Beta, Gamma, Delta, Epsilon and Iota Coronae Borealis. The German cartographer Johann Bayer gave twenty stars in Corona Borealis Bayer designations from Alpha to Upsilon in his 1603 star atlas Uranometria. Zeta Coronae Borealis was noted to be a double star by later astronomers and its components designated Zeta1 and Zeta2.
|
|
Pavlova Corona covers a circular area of around 400 km in diameter. Pavlova Corona is one of the four major coronae of eastern Eistla Regio (Didilia, Pavlova, Ninmah, and Isong). These coronae have relatively similar structure: an uplifted concentric feature with a central dome and surrounded by a relatively flat interior floor.
|
|
Nu Coronae Borealis is an optical double, whose components are a similar distance from Earth but have different radial velocities, hence are assumed to be unrelated. The primary, Nu1 Coronae Borealis, is a red giant of spectral type M2III and magnitude 5.2, lying 640±30 light-years distant, and the secondary, Nu2 Coronae Borealis, is an orange-hued giant star of spectral type K5III and magnitude 5.4, estimated to be 590±30 light-years away. Sigma Coronae Borealis, on the other hand, is a true multiple star system divisible by small amateur telescopes. It is actually a complex system composed of two stars around as massive as the Sun that orbit each other every 1.14 days, orbited by a third Sun-like star every 726 years.
|
|
Fotla Corona The geodynamic surface of Venus is dominated by patterns of basaltic volcanism, and by compressional and extensional tectonic deformation, such as the highly deformed tesserae terrain and the concentrically-fractured coronae. On Venus, coronae are large (typically several hundred kilometres across), crown-like, volcanic features. Coronae were first identified in 1983, when the radar imaging equipment aboard the Venera 15 and Venera 16 spacecraft produced higher-resolution images of some features previously thought to be impact craters. It is believed that coronae are formed when plumes of rising hot material in the mantle push the crust upwards into a dome shape, which then collapses in the centre as the molten magma cools and leaks out at the sides, leaving a crown-like structure: the corona.
|
|
Coronal stars are ubiquitous among the stars in the cool half of the Hertzsprung–Russell diagram. These coronae can be detected using X-ray telescopes. Some stellar coronae, particularly in young stars, are much more luminous than the Sun's. For example, FK Comae Berenices is the prototype for the FK Com class of variable star.
|
|
RS Coronae Borealis is yet another semiregular variable red giant, which ranges between magnitudes 8.7 to 11.6 over 332 days. It is unusual in that it is a red star with a high proper motion (greater than 50 milliarcseconds a year). Meanwhile, U Coronae Borealis is an Algol-type eclipsing binary star system whose magnitude varies between 7.66 and 8.79 over a period of 3.45 days TY Coronae Borealis is a pulsating white dwarf (of ZZ Ceti) type, which is around 70% as massive as the Sun, yet has only 1.1% of its diameter.
|
|
Nicolas Louis de Lacaille gave Epsilon Coronae Australis its Bayer designation. It is also known as HR 7152, and HD 175813.
|
|
Zeta Coronae Australis is a rapidly rotating main sequence star with an apparent magnitude of 4.8, 221.7 light years from Earth. The star has blurred lines in its hydrogen spectrum due to its rotation. Its spectral type is B9V. Theta Coronae Australis lies further to the west, a yellow giant of spectral type G8III and apparent magnitude 4.62.
|
|
Gamma Coronae Australis (γ CrA), is a binary star located in the constellation Corona Australis. The system has a combined apparent visual magnitude of 4.20, making it faintly visible to the naked eye. It is located 56.4 light-years (17.3 parsecs) from the Sun, based on its parallax. Gamma Coronae Australis is a member of the Milky Way's thin disk.
|
|
This is an evolved red giant star with a stellar classification of K5 III. The measured angular diameter of Nu2 Coronae Borealis is . At its estimated distance, this yields a physical size of about 50 times the radius of the Sun. Nu2 Coronae Borealis is radiating 530 times the Sun's luminosity from its photosphere at an effective temperature of 3,940 K.
|
|
The small Uranian ovoid features coronae that are very large in relation to its size. They may be formed by diapirs: upwellings of warm ice.
|
|
Normally placid around magnitude 10—it has a minimum of 10.2 and maximum of 9.9—it brightens to magnitude 2 in a period of hours, caused by a nuclear chain reaction and the subsequent explosion. T Coronae Borealis is one of a handful of stars called recurrent novae, which include T Pyxidis and U Scorpii. An outburst of T Coronae Borealis was first recorded in 1866; its second recorded outburst was in February 1946. T Coronae Borealis is a binary star with a red-hued giant primary and a white dwarf secondary, the two stars orbiting each other over a period of approximately 8 months.
|
|
Batrachedra nuciferae is a moth in the family Batrachedridae. It is found in Brazil. The larvae have been recorded feeding on Attalea, Cocos nucifera, and Syagrus coronae.
|
|
TY Coronae Australis ranges irregularly between magnitudes 8.7 and 12.4, and the brightness of the nebula varies with it. Blue-white, it is of spectral type B8e. The largest young stars in the region, R, S, T, TY and VV Coronae Australis, are all ejecting jets of material which cause surrounding dust and gas to coalesce and form Herbig–Haro objects, many of which have been identified nearby.
|
|
The coronae, which are unique to Miranda, initially defied easy explanation; one early hypothesis was that Miranda, at some time in its distant past, (prior to any of the current cratering) had been completely torn to pieces, perhaps by a massive impact, and then reassembled in a random jumble. The heavier core material fell through the crust, and the coronae formed as the water re-froze. However, the current favoured hypothesis is that they formed via extensional processes at the tops of diapirs, or upwellings of warm ice from within Miranda itself. The coronae are surrounded by rings of concentric faults with a similar low-crater count, suggesting they played a role in their formation.
|
|
These are giants of spectral types G and K with an unusually rapid rotation and signs of extreme activity. Their X-ray coronae are among the most luminous (Lx ≥ 1032 erg·s−1 or 1025W) and the hottest known with dominant temperatures up to 40 MK. The astronomical observations planned with the Einstein Observatory by Giuseppe Vaiana and his group showed that F-, G-, K- and M-stars have chromospheres and often coronae much like our Sun. The O-B stars, which do not have surface convection zones, have a strong X-ray emission. However these stars do not have coronae, but the outer stellar envelopes emit this radiation during shocks due to thermal instabilities in rapidly moving gas blobs.
|
|
Also A-stars do not have convection zones but they do not emit at the UV and X-ray wavelengths. Thus they appear to have neither chromospheres nor coronae.
|
|
Other cultures have likened the pattern to a turtle, ostrich nest, a tent, or even a hut belonging to a rock hyrax. Although fainter than its northern counterpart, the oval- or horseshoe-shaped pattern of its brighter stars renders it distinctive. Alpha and Beta Coronae Australis are the two brightest stars with an apparent magnitude of around 4.1. Epsilon Coronae Australis is the brightest example of a W Ursae Majoris variable in the southern sky.
|
|
Gamma Coronae Borealis, Latinized from γ Coronae Borealis, is a binary star system in the northern constellation of Corona Borealis. It is visible to the naked eye with an apparent visual magnitude of 3.83. Based upon an annual parallax shift of 22.33 mas as seen from Earth, it is located about 146 light years from the Sun. The system is moving closer to the Sun with a radial velocity of about −15 km/s.
|
|
In 1969, γ Coronae Borealis was confirmed to be variable with an amplitude of 0.05 magnitudes. A year later, it was "confirmed" to be a δ Scuti variable with the earliest known spectral type in the class. The observed variations were not strictly periodic, but showed a characteristic timescale of 0.03 days (43 minutes). γ Coronae Borealis also showed anomalous behaviour not seen in other δ Scuti stars, such as periods without variation.
|
|
Upsilon Coronae Borealis, Latinized from υ Coronae Borealis, is a solitary star in the northern constellation of Corona Borealis. It is a white-hued star that is dimly visible to the naked eye with an apparent visual magnitude of 5.78. The distance to this object is approximately based on parallax. This is an A-type main-sequence star with a stellar classification of A3V; a star that is currently fusing its core hydrogen.
|
|
At the southern end of the crown asterism are the stars Eta¹ and Eta² Coronae Australis, which form an optical double. Of magnitude 5.1 and 5.5, they are separable with the naked eye and are both white. Kappa Coronae Australis is an easily resolved optical double—the components are of apparent magnitudes 6.3 and 5.6 and are about 1000 and 150 light years away respectively. They appear at an angle of 359 degrees, separated by 21.6 arcseconds.
|
|
Epsilon Coronae Australis is an F4V dwarf star with an effective temperature of 6000 Kelvin. It ranges between apparent magnitudes of 4.74 to 5 over 14 hours, an absolute magnitude of +2.45, and a mass of 1.1 solar masses. Epsilon Coronae Australis is a W Ursae Majoris variable, indicating that it has a contact companion within the Roche Limit of the primary. The star is located at a distance of 30 pc (97 light years) from the Sun.
|
|
Zeta Coronae Australis (ζ Coronae Australis) is a solitary, blue-white hued star located in the southern constellation Corona Australis. With an apparent visual magnitude of +4.75, it is sufficiently bright to be viewed with the naked eye. Based upon an annual parallax shift of 16.89 mas as seen from Earth, this star is located around 193 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.15 due to interstellar dust.
|
|
Pi Coronae Borealis, Latinized from π Coronae Borealis, is a solitary, orange- hued star in the northern constellation of Corona Borealis. Its apparent magnitude is 5.58, which is bright enough to be faintly visible to the naked eye. Based upon an annual parallax shift of 13.40 mas as measured from Earth, it is located about 243 light years from the Sun. The star is moving closer to the Sun with a radial velocity of −5 km/s.
|
|
Omicron Coronae Borealis, Latinized from o Coronae Borealis, is a star in the northern constellation of Corona Borealis. It is a faint star but visible to the naked eye on a dark night with an apparent visual magnitude of +5.53. The annual parallax shift of the star as seen from Earth is 12.08 mas, which provides a distance estimate of around 270 light years. It is moving closer to the Sun with a radial velocity of −54 km/s.
|
|
In 2020, a study by University of Maryland supported by Swiss National Science Foundation and NASA discovered that 37 of Venus coronae show signs of ongoing activity. Maryland professor Laurent Montesi said, "we are able to point to specific structures and say ‘Look, this is not an ancient volcano but one that is active today, dormant perhaps, but not dead..." The active coronae are clustered near each other, so positioning geologic survey instruments would now be easier.
|
|
Structures primarily found in the plains of Guinevere Planitia consist of wrinkle ridges, fractures and lineaments. Lineaments exhibit one dominant orientation of tectonic features. Extending through the plains of Guinevere is a deformation zone that is made up of discontinuous segments of lineament belts and ovoids that are referred to as the Beta-Eistla deformation zone. Other structural features are observed in coronae and coronae-like features as well as tesserae and other highly tectonized units.
|
|
Tau Coronae Borealis, Latinized from τ Coronae Borealis, is a possible astrometric and spectroscopic binary star system in the northern constellation of Corona Borealis. It is visible to the naked eye with an apparent visual magnitude of 4.76. Tau CrB has a visible companion of visual magnitude 13.2 and they have been treated as a common proper motion pair. As of 2014, the pair had an angular separation of 2.20 arc seconds along a position angle of 186°.
|
|
Iota Coronae Borealis, Latinized from ι Coronae Borealis, is a binary star system in the constellation Corona Borealis. It is visible to the naked eye with a combined apparent visual magnitude of is 4.96. Based upon an annual parallax shift of 10.46 mas as seen from the Earth, it is located about 312 light years from the Sun. This is a single-lined spectroscopic binary with an orbital period of 35.5 days and an eccentricity of 0.56.
|
|
R Coronae Borealis is a faint naked eye star, but does not have any traditional names. Johann Bayer did not give it a Greek letter designation although it is marked on his map. John Flamsteed numbered all the Bayer stars but did not add any additional designations for fainter stars, so R Coronae Borealis does not appear in either of these two catalogues. At its discovery it was described simply as "the variable in the Northern crown".
|
|
None of the single magnetic stars has been seen as of 1999 as an X-ray source, although fields are of direct relevance to the maintenance of coronae in main sequence stars.
|
|
W Coronae Borealis (W CrB) is a Mira-type long period variable star in the constellation Corona Borealis. Its apparent magnitude varies between 7.8 and 14.3 over a period of 238 days.
|
|
Epsilon Coronae Borealis, Latinized from ε Coronae Borealis, is a multiple star system in the constellation Corona Borealis located around 230 light- years from the Solar System. It shines with a combined apparent magnitude of 4.13, meaning it is visible to the unaided eye in all night skies except those brightly lit in inner city locations. It is an orange giant around 1.7 times as massive as the Sun of spectral type K2III, which has exhausted its core fuel supply of hydrogen and swollen to 21 times the Sun's diameter and 151 times its luminosity. That is, Epsilon Coronae Borealis's diameter is about one-quarter of Mercury's orbit. Its surface temperature has been calculated to be 4365 ± 9 K, or 4406 ± 15 K. It is thought to be around 1.74 billion years old. Epsilon Coronae Borealis B is a companion star thought to be an orange dwarf of spectral types K3V to K9V that orbits at a distance of 135 astronomical units, completing one orbit every 900 years.
|
|
The smaller star is of spectral type F2V with a surface temperature of around 6750 K, and has around , , and between 4 and . Near Nusakan is Theta Coronae Borealis, a binary system that shines with a combined magnitude of 4.13 located 380±20 light-years distant. The brighter component, Theta Coronae Borealis A, is a blue-white star that spins extremely rapidly—at a rate of around 393 km per second. A Be star, it is surrounded by a debris disk.
|
|
X1822–371, associated with the optically visible star V691 Coronae Australis (abbreviated V691 CrA), is a neutron-star X-ray binary system at a distance of approximately 2-2.5 kiloparsecs. It is known to have a high inclination of i = 82.5°± 1.5°. This source displays relatively high brightness in the optical wavelengths when compared to the X-ray, making it a prototypical Accretion Disk Coronae (ADC) source, i.e. a source with a corona extending above and below its accretion disk.
|
|
T Coronae Australis (T CrA), is a young star in the constellation Corona Australis. Slightly less luminous than our Sun, it has a spectral type of F0 and is surrounded by a circumstellar disk.
|
|
It could then become an AM CVn system or merge to make a R Coronae Borealis star. The orbit compares with V407 Vulpeculae with a 9.5 minute orbit, and HM Cancri with 5.4 minute orbit.
|
|
A very young star, it is still accumulating interstellar material. It is obscured by, and illuminates, the surrounding nebula, NGC 6729, which brightens and darkens with it. The nebula is often compared to a comet for its appearance in a telescope, as its length is five times its width. S Coronae Australis is a G-class dwarf in the same field as R and is a T Tauri star. Nearby, another young variable star, TY Coronae Australis, illuminates another nebula: reflection nebula NGC 6726–7.
|
|
Kappa Coronae Borealis, Latinized from κ Coronae Borealis, is a star approximately 98 light years away in the constellation of Corona Borealis. The apparent magnitude is +4.82 (4.17 trillion times fainter than the Sun) and the absolute magnitude is +2.35 (9.82 times brighter than the Sun). It is an orange K-type subgiant star of spectral type K1IV, meaning it has nearly completely exhausted its hydrogen supply in its core. It is 1.32 times as massive as the Sun yet has brightened to 11.6 times its luminosity.
|
|
Consequently, the Chinese name for Alpha Coronae Australis itself is (, .). 香港太空館 - 研究資源 - 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010.
|
|
Consequently, the Chinese name for Alpha Coronae Borealis itself is (, .). 香港太空館 - 研究資源 - 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010.
|
|
T Coronae Borealis (T CrB), is a recurring nova in the constellation Corona Borealis. It was first discovered in outburst in 1866 by John Birmingham, although it had been observed earlier as a 10th magnitude star.
|
|
UX Antliae is post-AGB star. It is an R Coronae Borealis variable star that has a base apparent magnitude of around 11.85, with irregular dimmings down to below magnitude 18.0. Researchers David Kilkenny and J.E. Westerhuys of the South African Astronomical Observatory confirmed that UX Antliae was an R Coronae Borealis variable in 1990 after noting the similarity of its spectrum to the RCB star W Mensae. It had been suspected of being one since 1940, but had been little-studied and exhibited no characteristic declines between 1975 and 1990.
|
|
Flanking Alpha to the east is Gamma Coronae Borealis, yet another binary star system, whose components orbit each other every 92.94 years and are roughly as far apart from each other as the Sun and Neptune. The brighter component has been classed as a Delta Scuti variable star, though this view is not universal. The components are main sequence stars of spectral types B9V and A3V. Located 170±2 light-years away, 4.06-magnitude Delta Coronae Borealis is a yellow giant star of spectral type G3.5III that is around and has swollen to .
|
|
The system is a visual binary, where the orbit is calculated from observations of one star orbiting the other. The primary, Gamma Coronae Australis A, is a late F-type main-sequence star with an effective temperature of 6,090 K. It has an absolute an absolute magnitude of +3.73, and a mass of 1.15 solar masses. The secondary, Gamma Coronae Australis B, is also F-type. With an effective temperature of 6,100 K, an absolute magnitude of +3.80, and a mass of 1.14 solar masses, the companion is almost identical to the primary.
|
|
It is one of the three brightest R Coronae Borealis stars visible to Earth observers, along with R Coronae Borealis and V854 Centauri, and the brightest in the southern hemisphere. It is also a pulsating variable, with a semiregular period of 38 days. Its light curve has been studied for over a hundred years and is typical for the class, characterised by a sudden drop in brightness of several magnitudes over a few weeks before gradually brightening over the following several months. The timing between these dimmings is irregular.
|
|
RS Coronae Borealis is a semiregular variable star located in the constellation Corona Borealis with a parallax of 2.93mas being a distance of .SIMBAD, RS Coronae Borealis (accessed 20 February 2013) It varies between magnitudes 8.7 to 11.6 over 332 days. It is unusual in that it is a red star with a high proper motion (greater than 50 milliarcseconds a year). Located around 1072 light-years distant, it shines with a luminosity approximately 1839 times that of the Sun and has a surface temperature of 3340 K.
|
|
In March 2013, it was announced that resolved images of at least one dust disk surrounding Kappa Coronae Borealis were captured, making it the first subgiant to host such circumstellar belt. The disk extends out to 120 AU.
|
|
Visual light curve for RY Sagittarii, 1988–2015, showing classic behaviour for this type of variable An R Coronae Borealis variable (abbreviated RCB, R CrB) is an eruptive variable star that varies in luminosity in two modes, one low amplitude pulsation (a few tenths of a magnitude), and one irregular, unpredictably-sudden fading by 1 to 9 magnitudes. The prototype star R Coronae Borealis was discovered by the English amateur astronomer Edward Pigott in 1795, who first observed the enigmatic fadings of the star. Only about 150 RCB stars are currently known in our Galaxy while up to 1000 were expected, making this class a very rare kind of star. It is increasingly suspected that R Coronae Borealis (RCB) stars – rare hydrogen-deficient and carbon-rich supergiant stars – are the product of mergers of white-dwarfs in the intermediary mass regime (total mass between 0.6 and 1.2 ).
|
|
Clonuncaria coronae is a species of moth of the family Tortricidae. It is found in Minas Gerais, Brazil. The wingspan is about 11 mm. The ground colour of the forewings is brownish cream, with somewhat darker suffusions and strigulations (fine streaks).
|
|
It has a surface temperature of 5180 K. For most of its existence, Delta Coronae Borealis was a blue-white main-sequence star of spectral type B before it ran out of hydrogen fuel in its core. Its luminosity and spectrum suggest it has just crossed the Hertzsprung gap, having finished burning core hydrogen and just begun burning hydrogen in a shell that surrounds the core. Zeta Coronae Borealis is a double star with two blue-white components 6.3 arcseconds apart that can be readily separated at 100x magnification. The primary is of magnitude 5.1 and the secondary is of magnitude 6.0.
|
|
Beta Coronae Australis, Latinized from β Coronae Australis, is a single star in the southern constellation of Corona Australis. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.10. The star is located around 470 light years distant from the Sun based on parallax, and is drifting further away with a radial velocity of +3 km/s. This is an aging K-type giant/bright giant star with a stellar classification of K0II/IIICNIb, where the suffix notation indicates an abundance anomaly of CN in the spectrum.
|
|
Their surfaces are heavily cratered, though all of them (except Umbriel) show signs of endogenic resurfacing in the form of lineaments (canyons) and, in the case of Miranda, ovoid race-track like structures called coronae. Extensional processes associated with upwelling diapirs are likely responsible for the origin of the coronae. Ariel appears to have the youngest surface with the fewest impact craters, while Umbriel's appears oldest. A past 3:1 orbital resonance between Miranda and Umbriel and a past 4:1 resonance between Ariel and Titania are thought to be responsible for the heating that caused substantial endogenic activity on Miranda and Ariel.
|
|
R Coronae Borealis is a low-mass yellow supergiant star in the constellation of Corona Borealis. It is the prototype of the R Cor Bor class of variable stars, which fade by several magnitudes at irregular intervals. R Coronae Borealis itself normally shines at approximately magnitude 6, just about visible to the naked eye, but at intervals of several months to many years fades to as faint as 15th magnitude. Over successive months it then gradually returns to its normal brightness, giving it the nickname "reverse nova", after the more common type of star which rapidly increases in brightness before fading.
|
|
Scorpius's tail represents a suckerfish, while Eta Sagittarii and Theta Coronae Australis mark the bottom of the canoe. On the island of Futuna, the figure of Corona Australis was called Tanuma and in the Tuamotus, it was called Na Kaua-ki-Tonga.
|
|
The features observed provide evidence for the geological processes at work. Twenty feature types have been categorized thus far. These classes include local features, such as craters, coronae, and undae, as well as regional-scale features, such as planitiae, plana, and tesserae.
|
|
Epsilon Coronae Australis (ε CrA), is a star system located in the constellation Corona Australis. Varying in brightness between apparent magnitudes of 4.74 to 5 over 14 hours, it is the brightest W Ursae Majoris variable (low mass contact binary) in the night sky.
|
|
Theta Coronae Australis has an unusually high rate of rotation for an evolved star of this type, showing a projected rotational velocity of 11.8 km/s. One possible explanation is that it may have engulfed a nearby giant planet, such as a hot Jupiter.
|
|
RY Sagittarii is a yellow supergiant and an R Coronae Borealis type variable star in the constellation Sagittarius. Although it ostensibly has the spectrum of a G-type star, it differs markedly from most in that it has almost no hydrogen and much carbon.
|
|
U Aquarii (U Aqr) is a star in the constellation of Aquarius. It has an apparent visual magnitude which varies between 10.6 and 15.9. In 1999, U Aqr was proposed to be a Thorne-Zytkow object, instead of being a simple R Coronae Borealis variable.
|
|
Extrasolar planets have been confirmed in five star systems, four of which were found by the radial velocity method. The spectrum of Epsilon Coronae Borealis was analysed for seven years from 2005 to 2012, revealing a planet around 6.7 times as massive as Jupiter () orbiting every 418 days at an average distance of around 1.3 AU. Epsilon itself is a orange giant of spectral type K2III that has swollen to and . Kappa Coronae Borealis is a spectral type K1IV orange subgiant nearly twice as massive as the Sun; around it lie a dust debris disk, and one planet with a period of 3.4 years. This planet's mass is estimated at .
|
|
Of spectral type B6Vnn, Theta Coronae Borealis A is around six times as massive as the Sun and has four times the diameter. It has a surface temperature of around 14910 K. In 1970, it faded by 0.7 magnitude, becoming 50% fainter. The cause for this is unknown, but thought possibly due to ejection of dust that obscured the star's light. Theta Coronae Borealis B is a white main sequence star of spectral type A2V that is around 2.5 times as massive as the Sun and located 86 astronomical units from the primary star, the two stars taking an estimated 300 years to orbit around a common centre of gravity.
|
|
Gamma Coronae Australis has been known to be a binary for a long time, and its two components have been given Henry Draper Catalogue designations of HD 177474 and HD 177475, respectively. The two stars are separated by 1.896″ and orbit each other every 121.76 years.
|
|
RT Normae is an R Coronae Borealis type variable star in the constellation Norma. It has a baseline magnitude of 9.8, dropping down to 14.7 at its minima. It has less than 55% the mass of the Sun and an effective (surface) temperature of around 7000 K.
|
|
The Corona Formation has provided fossils of fish, brachiopods, a bryozoan, an insect, fossil flora including trunks and ichnofossils ascribed to Limnopus. The tracks from the Corona Formation include the oldest record of tetrapod tracks from the Southern Alps. The rugose coral Amplexus coronae was named after the formation.
|
|
The Coronet cluster, about 554 light years (170 parsecs) away at the edge of the Gould Belt, is also used in studying star and protoplanetary disk formation. R Coronae Australis is an irregular variable star ranging from magnitudes 9.7 to 13.9. Blue-white, it is of spectral type B5IIIpe.
|
|
S. coronata nuts are the favored food of Lear's macaw, whose bill size and shape are particularly adapted to crack them. Syagrus species are used as food plants by the larvae of some Lepidoptera species including Batrachedra nuciferae (recorded on S. coronae) and Paysandisia archon (recorded on S. romanzoffiana).
|
|
The planet is 1.8 Jupiter masses, or 570 Earth masses, although only the minimum mass is known since the inclination is not known. It orbits at a distance of 2.7 astronomical units, or 400 gigameters, and takes 1,208 days, or 3.307 years, to orbit around Kappa Coronae Borealis.
|
|
Published by 台灣書房出版有限公司, 2005, . Consequently, the Chinese name for Beta Coronae Borealis itself is (, ). 香港太空館 - 研究資源 - 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010.
|
|
The following early-type galaxies (NGCs) have been observed to be X-ray bright due to hot gaseous coronae: 315, 1316, 1332, 1395, 2563, 4374, 4382, 4406, 4472, 4594, 4636, 4649, and 5128. The X-ray emission can be explained as thermal bremsstrahlung from hot gas (0.5–1.5 keV).
|
|
The broad region of Lada Terra contains massive coronae, rift zones, and volcanic plains as well as many other features that scientists use to attempt to piece together the history of this complex planet. The distinctive cross-cutting relationships found in the bedding of Lada Terra have been important in realizing relative ages of the extensional belts and coronae, as well as the complex tesserae features present planet-wide. In 1990 the Venus Radar Mapper revealed the largest outflow channel system on the planet located in the northern region of Lada Terra. Although Lada Terra is generally considered a highland of Venus, the topography is much lower-lying than its northern counterparts Ishtar Terra and Aphrodite Terra.
|
|
John Birmingham (1816–1884) was an Irish astronomer, amateur geologist, polymath and poet. He spent six or seven years travelling widely in Europe where he became proficient in several languages. In 1866 he discovered the recurrent nova T Coronae Borealis. He studied and wrote articles on planets, meteor showers and sunspots.
|
|
Aphnaeus brahami, the western silver spot, is a butterfly in the family Lycaenidae. It is found in Senegal, Burkina Faso, Ghana (the Volta Region), Benin and Nigeria. The habitat consists of the Guinea/Sudan savanna transition zone. The former species Aphnaeus coronae, found in Sudan, Uganda and Kenya, is now included in A. brahami.
|
|
Halfway between Theta Coronae Australis and Theta Scorpii is the dense globular cluster NGC 6541. Described as between magnitude 6.3 and magnitude 6.6, it is visible in binoculars and small telescopes. Around 22000 light years away, it is around 100 light years in diameter. It is estimated to be around 14 billion years old.
|
|
U Coronae Borealis (U CrB) is an Algol-type eclipsing binary star system in the constellation Corona Borealis. Its apparent magnitude varies between 7.66 and 8.79 over a period of 3.45 days The component stars are a blue-white main sequence star of spectral type B6V and a cooler yellow-white subgiant star of spectral type F8III-IV.
|
|
Margaret of Austria, as Duchess of Florence and Parma, chose for her device a pearl shining from its shell, with the motto, Decus allatura coronae ("About to bring glory to the crown").Vinycomb, J. (1883). The Daisy as an Impress or Device. The Journal of the Royal Historical and Archaeological Association of Ireland, 6(56), fourth series, p. 208.
|
|
Volcano-dominated rises, such as the Bell Regio, have volcanoes atop the topographic rise. Rift-dominated rises are uplifted by rifting and thinning of the lithosphere and include the Beta Regio and the overlying Theia Mons. In a coronae-dominated rise, uplift is caused by the gravitational collapse and extension of a magma chamber, and include the Themis Regio.
|
|
The Zodiacal Light Observatory currently consists of two instruments. The Scatter-free Observatory for Limb Active Regions and Coronae (SOLARC or SOLAR-C) telescope is a off-axis reflecting coronagraph that is used to study the Sun's corona. The Day-Night Seeing Monitor Telescope System (DNSM) makes telescope-independent observations of perturbations in the atmosphere above Haleakala.
|
|
Evidence suggests the reorientation would have been as extreme as 60 degrees from the sub-Uranian point. The positions of all the coronae require a tidal heating pattern consistent with Miranda being solid, and lacking an internal liquid ocean. It is believed through computer modelling that Miranda may have an additional corona on the unimaged hemisphere.
|
|
DY Persei is a variable star and carbon star in the Perseus constellation. At maximum it is 11th magnitude carbon star and at its faintest it drops to 16th magnitude. DY Persei the prototype of the very rare DY Persei class of variables, that pulsate like red variables but also fade from sight like R Coronae Borealis variables.
|
|
Moira Mary Jardine is a British astrophysicist with an interest in young stars, particularly the structure of their magnetic fields and coronae, and the mechanisms by which they interact with their disks and planets. She was promoted to a Personal Chair in 2012, making her the first female professor of Physics at the University of St Andrews.
|
|
Alpha Coronae Australis belongs to the spectral class A2Va, making it an A-type star like Vega. Like the latter, it has excess infrared radiation, which indicates it may be ringed by a disk of dust. It has an apparent magnitude of +4.10. The star's mass and radius are estimated at 2.3 times the Sun's mass and radius.
|
|
It is common to find groups of hundreds of these volcanoes in areas called shield fields. The domes of Venus are between 10 and 100 times larger than those formed on Earth. They are usually associated with "coronae" and tesserae. The pancakes are thought to be formed by highly viscous, silica-rich lava erupting under Venus's high atmospheric pressure.
|
|
For the most part, lava flow fields are associated with volcanoes. The central volcanoes are surrounded by extensive flows that form the core of the volcano. They are also related to fissure craters, coronae, dense clusters of volcanic domes, cones, wells and channels. Thanks to Magellan, more than 200 channels and valley complexes have been identified.
|
|
RZ Normae is an R Coronae Borealis type variable star in the constellation Norma. It has a baseline magnitude of 10.2, dropping down to dimmer than 16.2 at its minima. It was discovered by the astronomer Sergei Gaposchkin in 1952. It has around 60% the mass of the Sun and an effective (surface) temperature of around 6750 K.
|
|
Forbidden "nebular" lines of [OI], [OII], and [NII] can be detected at times. The spectrum at maximum indicates that hydrogen in R Coronae Borealis is strongly depleted, helium is the dominant element, and carbon is strongly enhanced. At minimum, the spectrum shows the development of carbon clouds that obscure the photosphere, leaving chromospheric lines visible at times.
|
|
Research in 1996 revealed that Sakurai's Object possessed the characteristics of a R Coronae Borealis variable star with the anomaly of Carbon-13 (13C) deficit. Also, the metallicity of Sakurai's object in 1996 was similar to that of V605 Aquilae in 1921. However, it is expected that Sakurai's object will grow in its metallicity to match that of V605 Aquilae.
|
|
Kappa Coronae Borealis b is an extrasolar planet approximately 98 light-years away in the constellation of Corona Borealis. This planet was discovered by Johnson et al., who used the radial velocity method to detect wobbling of the star caused by a planet move around by its tug of gravity. It was first discovered in September 2007 and was published in November.
|
|
The calotte is a Belgian student cap worn by students attending Catholic universities. They are emblems of student folklore dating back to the late 19th century. Nowadays, most calottes are passed by way of a ceremony known as the coronae. How they are passed and what must be known or done to deserve it depends on the Cercle or Régionale.
|
|
However, Palmer et al. (1968) had it classed as type A2IV, and thus it may be near or past its main sequence lifetime. It is a suspected variable star of unknown type that has been measured ranging in brightness from magnitude 5.78 down to 5.88. Upsilon Coronae Borealis has three times the mass of the Sun and about 1.5 times the Sun's radius.
|
|
In Star Trek: The Next Generation (episode "Firstborn") and Star Trek: Deep Space Nine (episode "The Forsaken"), according to Star Trek: Star Charts, on the star chart labeled United Federation of Planets I, the Dopterians (an unscrupulous humanoid species found throughout the Alpha Quadrant) were from the Dopteria (Kappa Coronae Borealis) system. This system was located in the Alpha Quadrant.
|
|
The gradual restoration to normal brightness results from the dust being dispersed by radiation pressure. In August 2007, R Coronae Borealis began a fade to an unprecedented minimum. It fell to 14th magnitude in 33 days, then continued to fade slowly, dropping below 15th magnitude in June 2009. It then began an equally slow rise, not reaching 12th magnitude until late 2011.
|
|
R Coronae Borealis at maximum light shows the spectrum a late F or early G yellow supergiant, but with marked peculiarities. Hydrogen lines are weak or absent, while carbon lines and molecular bands of cyanogen (CN) and C2 are exceptionally strong. Helium lines and metals such as calcium are also present. The spectrum is variable, most obviously during the brightness fades.
|
|
His research on this spanned nearly three decades. Chandler also made contributions to other areas of astronomy, including variable stars. He independently co-discovered the nova T Coronae Borealis, improved the estimate of the constant of aberration, and computed the orbital parameters of asteroids and comets. Chandler was awarded the Gold Medal of the Royal Astronomical Society in 1896 and the James Craig Watson Medal in 1894.
|
|
Ganis Chasma consists of a group of rift zones located in the Ganiki Planitia Quadrangle on Venus. A chasma is defined as a long, narrow, steep sided depression on a planet. These depressions, or canyons, formed as a result of extensional tectonics due to volcanism. Ganis Chasma is associated with volcanism of Sapas Mons, a coronae feature located in the Alta Regio region of Venus.
|
|
In contrast to chimpanzees, a common morphological variant found in humans called Hirsuties coronae glandis, or pearly penile papules, are substantially larger, appear to be an outpocketing of both surface and underlying connective tissue layers, and lack the rich innervation seen in other animals.Glicksman, JM and Freeman, RG. Pearly penile papules. A statistical study of incidence. Arch. Dermatol. 93:56-59 (1966)Agrawal, SK et al.
|
|
The fourth and fifth components are a binary red dwarf system that is 14,000 AU distant from the other three stars. ADS 9731 is an even rarer multiple system in the constellation, composed of six stars, two of which are spectroscopic binaries. Corona Borealis is home to two remarkable variable stars. T Coronae Borealis is a cataclysmic variable star also known as the Blaze Star.
|
|
Cluster of newly formed stars in the Orion Nebula. Newly formed stars are known as pre-main-sequence stars during the stage of stellar evolution before they reach the main-sequence. Stars in this stage (ages <10 million years) produce X-rays in their stellar coronae. However, their X-ray emission is 103 to 105 times stronger than for main-sequence stars of similar masses.
|
|
Lying alongside the Milky Way, Corona Australis contains one of the closest star- forming regions to the Solar System—a dusty dark nebula known as the Corona Australis Molecular Cloud, lying about 430 light years away. Within it are stars at the earliest stages of their lifespan. The variable stars R and TY Coronae Australis light up parts of the nebula, which varies in brightness accordingly.
|
|
Like the star Vega, it has excess infrared radiation, which indicates it may be ringed by a disk of dust. It is currently a main-sequence star, but will eventually evolve into a white dwarf; currently, it has a luminosity 31 times greater, and a radius and mass of 2.3 times that of the Sun. Beta Coronae Australis is an orange giant 474 light years from Earth.
|
|
The nebula surrounds the variable star RU Coronae Australis, which has an average apparent magnitude of 12.9 and is a WC class Wolf–Rayet star. IC 1297 is small, at only 7 arcseconds in diameter; it has been described as "a square with rounded edges" in the eyepiece, elongated in the north-south direction. Descriptions of its color encompass blue, blue-tinged green, and green-tinged blue.
|
|
He became known as a kindly landlord but also as a scholar and intellectual. From 1858 He started contributing notes on astronomy to local newspapers. At Millbrook he built what The Tuam Herald called a large wooden house with a sliding roof, which formed his first observatory. On 12 May 1866 he discovered the variable star T Coronae Borealis in the constellation Corona Borealis.
|
|
Nu1 Coronae Borealis is a solitary, red-hued star located in the northern constellation of Corona Borealis. It is faintly visible to the naked eye, having an apparent visual magnitude of 5.20. Based upon an annual parallax shift of , it is located roughly 650 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.1 due to interstellar dust.
|
|
R Coronae Australis (R CrA) is a variable binary system in the constellation Corona Australis. It has varied between magnitudes 10 and 14.36. A small reflection/emission nebula NGC 6729 extends from the star towards SE. This star is moving toward the Solar System with a radial velocity of . It was previously believed that in roughly 222,000 years, this system could have approached within of the Sun.
|
|
Miranda has one of the most extreme and varied topographies of any object in the Solar System, including Verona Rupes, a 20-kilometer-high scarp that is the highest cliff in the Solar System, and chevron-shaped tectonic features called coronae. The origin and evolution of this varied geology, the most of any Uranian satellite, are still not fully understood, and multiple hypotheses exist regarding Miranda's evolution.
|
|
S Coronae Borealis was discovered to vary in brightness by German amateur astronomer Karl Ludwig Hencke in 1860. It was classified as a long period variable star as other similar objects were discovered, and later as a Mira variable. The maximum range of variation is from magnitude 5.8 to 14.1 although individual maxima and minima can vary in brightness. The period of 360 days is fairly predictable.
|
|
RS Telescopii is a star in the constellation Telescopium. It is a rare R Coronae Borealis variable—an extremely hydrogen-deficient supergiant thought to have arisen as the result of the merger of two white dwarfs; fewer than 100 have been discovered as of 2012. It has a maximum magnitude of 9.6 and a minimum magnitude 16.5. As of 2012, four dimmings have been observed.
|
|
RR Coronae Borealis (RR CrB, HD 140297, HIP 76844) is a M3-type semiregular variable star located in the constellation Corona Borealis with a parallax of 2.93mas being a distance of . It varies between magnitudes 7.3 and 8.2 over 60.8 days. Located around 1228 light-years distant, it shines with a luminosity approximately 2180 times that of the Sun and has a surface temperature of 3309 K.
|
|
These correspond to the first overtone and fundamental radial pulsation modes for an extreme helium star slightly under . At irregular intervals a few years or decades apart R Coronae Borealis fades from its normal brightness near 6th magnitude for a period of months or sometimes years. There is no fixed minimum, but the star can become fainter than 15th magnitude in the visual range.
|
|
TY Coronae Australis (abbreviated as TY CrA), is a young star system around 3 million years old in the constellation Corona Australis. It is composed of a blue-white B-class star around triple the Sun's mass and a cooler smaller companion around half its mass (or 1.6 times that of the Sun). The system is an eclipsing binary with a period of 2.8 days.
|
|
In classical mythology Corona Borealis generally represented the crown given by the god Dionysus to the Cretan princess Ariadne and set by him in the heavens. Other cultures likened the pattern to a circle of elders, an eagle's nest, a bear's den, or even a smokehole. Ptolemy also listed a southern counterpart, Corona Australis, with a similar pattern. The brightest star is the magnitude 2.2 Alpha Coronae Borealis.
|
|
Epsilon Coronae Australis is an eclipsing binary belonging to a class of stars known as W Ursae Majoris variables. These star systems are known as contact binaries as the component stars are so close together they touch. Varying by a quarter of a magnitude around an average apparent magnitude of 4.83 every seven hours, the star system lies 98 light years away. Its spectral type is F4VFe-0.8+.
|
|
When the two finally collide, the neutron star and red giant core will merge. If their combined mass exceeds the Tolman–Oppenheimer–Volkoff limit then the two will collapse into a black hole. Otherwise, the two will coalesce into a single neutron star. If a neutron star and a white dwarf merge, this could form a Thorne–Żytkow object with the properties of an R Coronae Borealis variable.
|
|
Nu2 Coronae Borealis is a solitary, orange-hued star located in the northern constellation of Corona Borealis. It is faintly visible to the naked eye, having an apparent visual magnitude of +5.4. Based upon an annual parallax shift of 5.49 mas, it is located roughly 590 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.1 due to interstellar dust.
|
|
In the event, Adrian was required to remain there for the next four months. As a result, although he had been consecrated, he had not been crowned in the ceremony dies coronae at the Lateran which gave him not his title but gave him feudal title of the papal lands. It is probable that, due to problematic relations with the Romans, he did not receive his crown until the following Easter.
|
|
Its parallax has been measured by very-long-baseline interferometry (VLBI), yielding a result of 2.39 ± 0.17 millarcseconds, which converts to a distance of 1300 ± 100 light-years. The masses of AGB stars are poorly known and cannot be calculated from their physical properties, but they can be estimated using asteroseismology. The pulsations of S Coronae Borealis lead to a mass estimate of 1.34 times that of the Sun.
|
|
Onatah Corona is a corona (a geological feature) on Venus adjacent to Ba'het Corona. Both features are surrounded by a ring of ridges and troughs, which in places cut more radially-oriented fractures. The centers of the features also contain radial fractures as well as volcanic domes and flows. Coronae are thought to form due to the upwelling of hot material from deep in the interior of Venus.
|
|
In Star Trek: Deep Space Nine (episodes "The Nagus", "Prophet Motive" and "Profit and Lace"), according to the Star Trek: Star Charts, on the star chart United Federation of Planets I, the Hupyrians (a humanoid species native to either the Alpha or Beta Quadrant) were from the Hupyria (Tau Coronae Borealis) system. Both the primary and the secondary were K-type stars. This system was located in the Alpha Quadrant.
|
|
Dutch astronomer Willem Jacob Luyten noted this star to be variable in 1935. Minima were retrospectively identified in old photographic plates from 1913 and 1919, and then observed by Howarth in 1936. Initially thought to be an R Coronae Borealis variable, its true nature as an eclipsing binary became clear in the 1940s. The primary component is a yellow supergiant, whose spectral type has been calculated as either F5Iab/b or F4Ib.
|
|
Delta Coronae Australis is a single star located in the southern constellation of Corona Australis. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.57. The star is located about 174 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +21 km/s. This object is an evolved giant star with a stellar classification of K1III.
|
|
Rho Coronae Borealis is a yellow main sequence star of the spectral type G0V. The star is thought to have only 91 percent of the Sun's mass, along with 1.4 times its radius and 1.7 times its luminosity. It may only be 51 to 65 percent as enriched with elements heavier than hydrogen (based on its abundance of iron) and may be somewhat older than the Sun at around ten billion years old.
|
|
S Apodis (HD 133444) is an R Coronae Borealis variable star located in the far southern constellation Apus. These are extremely hydrogen-deficient supergiants thought to have arisen as the result of the merger of two white dwarfs; fewer than 100 have been discovered as of 2012. Located around 13,000 light-years distant, it shines with a luminosity approximately 960 times that of the Sun and has a surface temperature of 3916 K.
|
|
Xi Coronae Borealis (ξ CrB) is a binary star system in the northern constellation of Corona Borealis. It is visible to the naked eye with a combined apparent visual magnitude of 4.85. Based upon an annual parallax shift of 17.78 mas as seen from the Earth, it is located about 183 light years from the Sun. As of 2009, the pair had an angular separation of 91 mas along a position angle of 139.4°.
|
|
The mechanism of variability for γ Coronae Borealis is not known. Spectroscopic variations with a period of 0.9 days have been observed, which matches the likely rotation period of the star, and radial velocity changes are also seen with a possible period of 0.45 days. Short-period non-radial pulsations may be carried around by the rotation of the star, but the driver of such pulsations in a star of this temperature is unknown.
|
|
A faint (magnitude 11.5) star, 1.5 arc minutes away, has been called Epsilon Coronae Borealis C although it is only close by line of sight and is unrelated to the system.SIMBAD, CCDM J15576+2652C -- Star in double system (accessed 16 November 2014) The ε CrB star system's radial velocity was observed over seven years from January 2005 to January 2012, during which time a 'wobble' with a period of around 418 days was recorded.
|
|
Its luminosity and spectrum suggest it has just crossed the Hertzsprung gap, having finished burning core hydrogen and just begun burning hydrogen in its shell. It is a strong source of X-rays due to its hot corona. In 1989, it was noticed that the brightness of δ Coronae Borealis is not constant. Approximately every 45 days, its brightness changes sinusoidally between 4.57 and 4.69, too small to be noticed without close monitoring.
|
|
Its radius has been calculated to be 61 times that of the Sun. The variability of W Men was discovered in 1927 by W. J. Luyten. It belongs to the very rare R Coronae Borealis class of variables which are often called "inverse novae" since they experience occasional very large drops in brightness. At minimum brightness, W Men has a photographic (blue) magnitude less than +18.3, being undetectable on photographic plates at the time.
|
|
The X-ray Grating Spectrometer will be located on the Fixed Instrument Platform. This is a wavelength-dispersive spectrometer that will provide high spectral resolution in the soft X-ray band. It can be used to determine the properties of the warm-hot-intergalactic medium, outflows from active galactic nuclei, and plasma emissions from stellar coronae."Development of a critical-angle transmission grating spectrometer for the International X-Ray Observatory", Ralf K. Heilmann et al.
|
|
Kappa² is actually the brighter of the pair and is more bluish white, with a spectral type of B9V, while Kappa¹ is of spectral type A0III. Lying 202 light years away, Lambda Coronae Australis is a double splittable in small telescopes. The primary is a white star of spectral type A2Vn and magnitude of 5.1, while the companion star has a magnitude of 9.7. The two components are separated by 29.2 arcseconds at an angle of 214 degrees.
|
|
Both members of this system have active stellar coronae, show luminosity variations of the BY Draconis type, and are X-ray emitters. The average flare rate for the pair is 2.8 per hour. Their X-ray spectrum is consistent with a plasma density of around and a magnetic field strength of at least 100 G in the flare regions. Neither star shows any indication of lithium in their spectrum, having depleted this element through nuclear fusion at their cores.
|
|
The Coronet Cluster, also known as the R CrA cluster after its best-known member, is a small open cluster located about 170 parsecs away in the southern constellation Corona Australis, isolated at the edge of the Gould Belt. The Coronet Cluster is 3.5 times closer to the Earth than the Orion Nebula Cluster. The cluster center is composed of mostly young stars. The variable T Coronae Australis is also a member, only one arc minute from R CrA.
|
|
R Coronae Borealis-type deep minima in 1992 In 1943, a star designated AN 377.1943 was discovered to be a previously-unknown variable star. It was designated CSV 5066 as a suspected variable, and then FG Sagittae as a confirmed variable star. At the time, its variations were described as being irregular, but it was soon noted that the average brightness was steadily increasing. It brightened by about two magnitudes between 1943 and 1970, and then began to fade.
|
|
S Coronae Borealis is a cool red giant on the asymptotic giant branch (AGB). It pulsates, which causes its radius and temperature to change. One calculation found a temperature range of 2,350 K to 2,600 K, although a more modern calculation gives a temperature of 2,864 K. Similarly a calculation of the varying radius gives although a modern calculation of the radius gives . The bolometric luminosity varies much less than the visual magnitude and is estimated to be .
|
|
DY Persei variables are a subclass of R Coronae Borealis (R CrB) variables. They are carbon-rich asymptotic giant branch (AGB) stars that exhibit pulsational variability of AGB stars and irregular fades similar to R CrB stars. The star DY Persei is the prototype of this tiny class of variable stars. Only DY Persei itself was known in our galaxy until 2008 when systematic catalogue searches for R CrB variables discovered a 17th magnitude (at maximum) example.
|
|
NGC 6729 (also known as Caldwell 68) is a reflection/emission nebula in the constellation Corona Australis. It was discovered by Johann Friedrich Julius Schmidt in 1861. This fan-shaped nebula opens from the star R Coronae Australis toward the star T CrA to the south-east. R CrA is a pre-main- sequence star in the Corona Australis molecular complex, one of the closer star-forming regions of the galaxy at a distance of 130 pc.
|
|
These stars have masses lower than the sun, but luminosities that can be or higher, so they will become yellow supergiants for a short time. Post-AGB stars are believed to pulsate as RV Tauri variables when they cross the instability strip. The evolutionary status of yellow supergiant R Coronae Borealis variables is unclear. They may be post-AGB stars reignited by a late helium shell flash, or they could be formed from white dwarf mergers.
|
|
The dimensions of the debris disk indicate it is likely there is a second substellar companion. Omicron Coronae Borealis is a K-type clump giant with one confirmed planet with a mass of that orbits every 187 days—one of the two least massive planets known around clump giants. HD 145457 is an orange giant of spectral type K0III found to have one planet of . Discovered by the Doppler method in 2010, it takes 176 days to complete an orbit.
|
|
Eta1 Coronae Australis, Latinized from η1 CrA, is a suspected astrometric binary star system in the constellation of Corona Australis. It is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.456. Parallax measurements put it at a distance of 317 light- years away from the Sun. The visible component is an A-type main-sequence star with a stellar classification of A3V, which indicates it is generating energy through core hydrogen fusion.
|
|
In 1909 their observations of Algol detected for the first time the second minimum as well as limb brightening. The coming of Comet Halley in 1910 allowed Stebbins, in May, to use his selenium photometer to study the comet. Two years later Stebbins used the photometer and discovered four stars to be eclipsing binary stars: Beta Aurigae, Spica, Alpha Coronae Borealis and Delta Orionis. Although the selenium cell photometer was proving successful, it was difficult to use and not very sensitive.
|
|
These results provided the first detailed understanding of the surface geology of Venus, including the discovery of unusual massive shield volcanoes such as coronae and arachnoids. Venus had no evidence of plate tectonics, unless the northern third of the planet happened to be a single plate. The altimetry data obtained by the Venera missions had a resolution four times better than Pioneer's. A portion of western Eistla Regio displayed in a three- dimensional perspective view acquired by the Magellan probe.
|
|
Sternberg publishes the General Catalog of Variable Stars (GCVS), which is periodically (approximately once every two years) amended by the publication of a new "Name-List" of variable stars. For example, in December 2011 the 80th Name-List of Variable Stars, Part II, was released, containing designations for 2,161 recently discovered variable stars; these brought the total number of variable stars in the GCVS to 45,678. Among the newly designated objects were V0654 Aurigae, V1367 Centauri, and BU Coronae Borealis.
|
|
Circumferential ridges and graben are also highly reflective to radar, and therefore, easily observed around the Sappho Patera depression. These concentric features formed after Irnini Mons lost the high pressure dynamic support from the mantle upwelling due to the lack of overlying flows. The presence of circumferential structures along a shallow depression on Irnini Mons' summit is a characteristic of coronae on Venus. The presence of corona-like features suggest two possible theories for interpretation of how Irnini Mons developed.
|
|
A brown dwarf companion was detected in 2001. The source 2MASSW J1523226+301456 in the 2MASS working database was identified as having a similar proper motion to the AB binary, and subsequent observations confirmed its relationship to the system. The new component, Eta Coronae Borealis C, was found to have a spectral type of L8. The brown dwarf has a minimum separation of 3600 AU, and considering a cooling age of 1–2.5 gigayears, the brown dwarf has a mass of , or .
|
|
W Mensae (W Men) is an unusual yellow supergiant star in the Large Magellanic Cloud in the southern constellation Mensa. It is an R Coronae Borealis variable and periodically decreases in brightness by several magnitudes. W Men is very distant, being located in the neighboring galaxy Large Magellanic Cloud, where it lies on the southern metal-deficient edge. Despite its high luminosity, the star has a maximum apparent brightness of +13.8m, too dim to be visible in a small telescope.
|
|
In 1688 he wrote Jus regium Coronae, a learned defence of James's action in dispensing with the penal statutes. He died in obscurity, due perhaps to his political opinions, in 1696. Wilson was the author of four plays, showing a vigorous and learned wit, and a power of character-drawing that place him rather among the followers of Ben Jonson than with the Restoration dramatists. The Cheats (written in 1662, printed 1664, 1671) was played with great success in 1663.
|
|
Peter Francis Williams is an amateur astronomer from New South Wales, Australia. He specializes in early detection of declines in R Coronae Borealis-type stars and the long-term monitoring of several southern Mira variables and eclipsing binary stars. He was the first person who detected the naked-eye Nova known as V382 Velorum in 1999 and seven years later he discovered the Nova Ophiuchi 2006. Both discoveries brought him the Nova/Supernova Award of the American Association of Variable Star Observers.
|
|
While classed as eruptive variables, these stars do not undergo periodic increases in brightness. Instead they spend most of their time at maximum brightness, but at irregular intervals they suddenly fade by 1–9 magnitudes (2.5 to 4000 times dimmer) before recovering to their initial brightness over months to years. Most are classified as yellow supergiants by luminosity, although they are actually post-AGB stars, but there are both red and blue giant R CrB stars. R Coronae Borealis (R CrB) is the prototype star.
|
|
Cassinelli, J. P.; Macgregor, K. B. "Stellar chromospheres, coronae, and winds". Physics of the Sun. (1986). 3:47–123. Dordrecht, D. Reidel Publishing Co. Retrieved September 7, 2016. In 1996, Helmut Abt researched which papers published in 1954 were cited most frequently from 1955 to 1995, and Bidelman's Catalog and Bibliography ranked among the top four. Abt (1996) ranked Bidelman's paper fourth, because with 153 citations it had tied for third place with a paper by Walter Baade, and the two authors were listed alphabetically.
|
|
Hydrogen-deficient stars had been noted prior to the discovery of their hydrogen deficiency. In 1797, Edward Pigott noted the profound variation in stellar magnitude of R Coronae Borealis (R CrB). In 1867, Charles Wolf and Georges Rayet discovered unusual emission line structure in Wolf-Rayet stars. Hydrogen deficiency in a star was first discovered in 1891 by Williamina Fleming, where she stated “the spectrum of υ Sgr is remarkable since the hydrogen lines are very faint and of the same intensity as the additional dark lines”.
|
|
The true nature of the supernova remained obscure for some time. Observers slowly came to recognize a class of stars that undergo long-term periodic fluctuations in luminosity. Both John Russell Hind in 1848 and Norman Pogson in 1863 had charted stars that underwent sudden changes in brightness. However, these received little attention from the astronomical community. Finally, in 1866, English astronomer William Huggins made the first spectroscopic observations of a nova, discovering lines of hydrogen in the unusual spectrum of the recurrent nova T Coronae Borealis.
|
|
46 Boötis is a binary star system in the northern constellation of Boötes, located mid-way between α Coronae Borealis and ε Boötis. It has the Bayer designation b Boötis; 46 Boötis is the Flamsteed designation. The system lies 478 light years away from the Sun based on parallax, and is visible to the naked eye as a faint, orange-hued star with a combined apparent visual magnitude of 5.67. It is moving away from the Earth with a heliocentric radial velocity of +19 km/s.
|
|
Born into a family of Greek-Catholic peasants in Straja, Alba County, in the Transylvania region, he attended the Romanian high school in Blaj. Upon graduating in 1906, he enrolled in the theology faculty of Budapest University, which he completed in 1910. In 1912, he defended a doctoral thesis at the University of Vienna's theology faculty. Written in Latin and titled Relatio Rumenorum e terris coronae S[ancti] Stephani ad Reformationem saec[ulis] XVI et XVII, it dealt with interconfessional relations in Transylvania during the Reformation.
|
|
Large lava flow fields are described as flood-type lava that can be seen in fluctus fields. These are regions flooded with many low- viscosity volcanic flows from a single source that covers the area in a continuous flow field. Some flows may be radially distributed around a volcano of coronae as an apron, be fan-shaped, or sub-parallel in their orientation. Large flow fields may be sourced from large volcanoes, calderas, rift structures, or shield volcano fields and they are often associated with extensional environments.
|
|
Examination of old photographic observations found that the star had been brightening since at least 1900, with extrapolations suggesting that the minimum had occurred around 1880. As it faded, FG Sagittae began to show periodic variations, at first a period of 80 days, but increasing to 130 days. In 1992, the periodic variations ceased and the brightness decreased by five magnitudes in only two months. Since then, it has continued to show occasional deep fading events, appearing much like an R Coronae Borealis star.
|
|
However, the estimate had a considerable margin of error in it. With the release of Gaia DR2, the star was determined to be 4 times further from the Sun than initially believed, constraining the approach to only . A companion to the star was detected in 2019 with a mass between 0.1 and 1 Solar masses, depending on the characteristics of the stellar environment, orbiting the primary in 43–47 years. A colour photo of the R Coronae Australis region in the southern Milky Way.
|
|
Smalley's research in physical chemistry investigated formation of inorganic and semiconductor clusters using pulsed molecular beams and time-of-flight mass spectrometry. As a consequence of this expertise, Robert Curl introduced him to Harry Kroto in order to investigate a question about the constituents of astronomical dust. These are carbon-rich grains expelled by old stars such as R Coronae Borealis. The result of this collaboration was the discovery of C60 (Known as Buckyballs) and the fullerenes as the third allotropic form of carbon.
|
|
Eta Coronae Borealis has been known since the late 18th century to be a moderate-separation binary. The orbit of the two components takes approximately 42 years, which when combined with the distance to the system makes the two stars fairly easily resolvable with a larger telescope. The two stars have similar physical parameters, though the secondary is slightly cooler than the primary and has approximately 90% of the primary's mass. Possible stable planetary orbits in the habitable zone were calculated for the system in 1996.
|
|
UW Coronae Borealis, also known as MS 1603.6+2600, is a low-mass X-ray binary star system in the constellation Corona Borealis. Astronomer Simon Morris and colleagues discovered the X-ray source in 1990 and were able to match it up with a faint star with an average visual magnitude of 19.4. The system is thought to be made up of a neutron star that has an accretion disk that draws material from its companion, a star less massive than the Sun. The disk is asymmetrical.
|
|
Most of the new moons are small, with the largest measuring about in diameter. The moon Miranda, innermost of the five large moons, was revealed to be one of the strangest bodies yet seen in the Solar System. Detailed images from Voyager 2 flyby of the moon showed huge oval structures termed coronae flanked by faults as deep as , terraced layers, and a mixture of old and young surfaces. One theory holds that Miranda may be a reaggregation of material from an earlier time when the moon was fractured by a violent impact.
|
|
The hairy, oddly textured and coloured appearance of many Stapelia flowers has been claimed to resemble that of rotting meat, and this, coupled with their odour, has earned the most commonly grown members of the genus Stapelia the common name of carrion flowers. A notable exception is the sweetly scented Stapelia flavopurpurea. Such odours serve to attract various specialist pollinators including, in the case of carrion-scented blooms, blow flies of the dipteran family Calliphoridae. They frequently lay eggs around the coronae of Stapelia flowers, convinced by the plants' deception.PlantZAfrica.
|
|
The star system is one of the few eclipsing symbiotic binaries, but is unusual because the secondary star is not a white dwarf, but an A-type star. DY Persei is a variable star that is the prototype of DY Persei variables, which are carbon-rich R Coronae Borealis variables that exhibit the variability of asymptotic giant branch stars. DY Persei itself is a carbon star that is too dim to see through binoculars, with an apparent magnitude of 10.6. Seven stars in Perseus have been found to have planetary systems.
|
|
Lying 75±0.5 light-years from Earth, Alphecca is believed to be a member of the Ursa Major Moving Group of stars that have a common motion through space. Located 112±3 light-years away, Beta Coronae Borealis or Nusakan is a spectroscopic binary system whose two components are separated by 10 AU and orbit each other every 10.5 years. The brighter component is a rapidly oscillating Ap star, pulsating with a period of 16.2 minutes. Of spectral type A5V with a surface temperature of around 7980 K, it has around , 2.6 solar radii (), and .
|
|
X-ray emission for pre–main-sequence stars was discovered by the Einstein Observatory. This X-ray emission is primarily produced by magnetic reconnection flares in the stellar coronae, with many small flares contributing to the "quiescent" X-ray emission from these stars. Pre–main sequence stars have large convection zones, which in turn drive strong dynamos, producing strong surface magnetic fields. This leads to the high X-ray emission from these stars, which lie in the saturated X-ray regime, unlike main-sequence stars that show rotational modulation of X-ray emission.
|
|
Alpha and Beta are so similar as to be indistinguishable in brightness to the naked eye. Some of the more prominent double stars include Gamma Coronae Australis—a pair of yellowish white stars 58 light years away from Earth, which orbit each other every 122 years. Widening since 1990, the two stars can be seen as separate with a 100 mm aperture telescope; they are separated by 1.3 arcseconds at an angle of 61 degrees. They have a combined visual magnitude of 4.2; each component is an F8V dwarf star with a magnitude of 5.01.
|
|
Among the Uranian satellites, Ariel appears to have the youngest surface with the fewest impact craters and Umbriel's the oldest. Miranda has fault canyons deep, terraced layers, and a chaotic variation in surface ages and features. Miranda's past geologic activity is thought to have been driven by tidal heating at a time when its orbit was more eccentric than currently, probably as a result of a former 3:1 orbital resonance with Umbriel. Extensional processes associated with upwelling diapirs are the likely origin of Miranda's 'racetrack'-like coronae.
|
|
Hirsuties coronae glandis (also known as hirsutoid papillomas and pearly penile papules; PPP) are small protuberances that may form on the ridge of the glans of the human penis. They are a form of acral angiofibromas. They are a normal anatomical variation in humans and are sometimes described as vestigial remnants of penile spines, sensitive features found in the same location in other primates. In species in which penile spines are expressed, as well as in humans who have them, the spines are thought to contribute to sexual pleasure and quicker orgasms.
|
|
The Union of Krewo (; ) was a set of prenuptial agreements made in the Kreva Castle on August 13, 1385. Once Jogaila confirmed the prenuptial agreements on August 14, 1385, Poland and Lithuania formed a personal union. The agreements included the adoption of Christianity, repatriation of lands "stolen" from Poland by its neighbours, and terras suas Lithuaniae et Russiae Coronae Regni Poloniae perpetuo applicare, the clause which formed the personal union. After being baptized at the Wawel Cathedral in Kraków on February 15, 1386, Jogaila began to formally use the name Władysław.
|
|
We can draw an analogue of this lava flow to a flow that occurred on earth, the Deccan Traps igneous province in India. Compared to other corona on Venus, Quetzalpetlatl Corona not only exhibits the most massive lava flow, but is also composed of lava of relatively homogeneous composition as revealed by the variations in brightness using radar backscatter imaging. This is in contrast with most coronae on Venus, which exhibit lava flows of a more heterogeneous nature. The latter are interpreted as lava flows originating from very distinct source(s).
|
|
The office of the coroner dates from approximately the 11th century, shortly after the Norman conquest of England in 1066. The office of coroner was established by lex scripta in Richard I's England. In September 1194, it was decreed by Article 20 of the "Articles of Eyre" to establish the office of custos placitorum coronae (Latin for "keeper of the pleas of the Crown"), from which the word "coroner" is derived. This role provided a local county official whose primary duty was to protect the financial interest of the Crown in criminal proceedings.
|
|
Sebaceous glands are normal structures of the skin but may also be found ectopically in the mouth, where they are referred to as oral Fordyce granules or ectopic sebaceous glands. On the foreskin they are called Tyson's glands, not to be confused with hirsuties coronae glandis. When they appear on the penis, they are also called penile sebaceous glands. When seen as a streak of individual glands along the interface between the skin of the lip and the vermilion border, the terms Fox–Fordyce disease and Fordyce's condition have been used.
|
|
If the coronae formed through downwelling from a catastrophic disruption, then the concentric faults would present as compressed. If they formed through upwelling, such as by diapirism, then they would be extensional tilt blocks, and present extensional features, as current evidence suggests they do. The concentric rings would have formed as ice moved away from the heat source. The diapirs may have changed the density distribution within Miranda, which could have caused Miranda to reorient itself, similar to a process believed to have occurred at Saturn's geologically active moon Enceladus.
|
|
Several structures have been described as cometary knots or cometary globules that surround R Coronae Borealis, which is a peculiar star described as potentially the result of a white dwarf merger or final helium shell flash that periodically dims due to a build-up of carbon dust surrounding it, acting as a 'natural coronograph'. Three-dimensional modelling of NGC 6337, a planetary nebula with a close binary nucleus, suggests the presence of a "thick ring with radial filaments and knots." The cometary knots represent large density fluctuations in a slowly expanding toroid.
|
|
See table 1, IRAS 14003-7633. NO Apodis is a red giant of spectral type M3III that varies between magnitudes 5.71 and 5.95. Located 780 ± 20 light-years distant, it shines with a luminosity estimated at 2059 times that of the Sun and has a surface temperature of 3568 K. S Apodis is a rare R Coronae Borealis variable, an extremely hydrogen-deficient supergiant thought to have arisen as the result of the merger of two white dwarfs; fewer than 100 have been discovered as of 2012. It has a baseline magnitude of 9.7.
|
|
Volcanism is one of the fundamental processes of heat transfer from planetary interiors. By assessing the location of volcanic deposits and edifices, their volumes, and their sequences provide evidence for quantitative assessment of heat transfer in space and time. The region contains three major volcanoes which have smaller volcanic constructs built upon their flanks and summit regions: Atanua, Rhpisunt, Tuli, and Var Mons, and three coronae: Hulda, Madderakka, and Pölöznitsa. Due to the amount of flows from these major eruptive centers, there is much obscurities among the deposits.
|
|
Dipping from its baseline magnitude of 9.6 to 16.5, RS Telescopii is a rare R Coronae Borealis variable—an extremely hydrogen-deficient supergiant thought to have arisen as the result of the merger of two white dwarfs; fewer than 100 have been discovered as of 2012. The dimming is thought to be caused by carbon dust expelled by the star. As of 2012, four dimmings have been observed. PV Telescopii is a class B-type (blue) extreme helium star that is the prototype of a class of variables known as PV Telescopii variables.
|
|
Cameron's research primarily focuses on stellar magnetic fields and the discovery and characterisation of extra-solar planets and cool stars. In his early career, he focused on the rotational history and dynamo-generated magnetic activity of cool stars, ultimately producing micro-arcsecond resolution maps of starspot distributions and surface magnetic fields. With Dr R. D. Robinson he co-discovered the centrifugally supported "slingshot prominence" systems in the coronae of the young, rapidly rotating solar-type star AB Doradus and other similar objects. Cameron was awarded a personal chair in 2003.
|
|
Vestibular papillomatosis (VP) is a cutaneous condition of the vulva, characterized by pink, asymptomatic, fine projections of the vestibular epithelium or labia minora.no It is the female equivalent to hirsuties coronae glandis. It is often thought to be a human papillomavirus (HPV) infection, but several studies have shown that the condition is not viral and is not a sexually transmitted disease (STD). DNA studies have shown that any relation to HPV is purely coincidental (as a high percentage of the sexually active population has or has had HPV).
|
|
The temperature at maximum is reasonably well known at 6,900K and appears to decrease during the fades as the photosphere is obscured by condensing dust. The distance of R Coronae Borealis is not known exactly, but is estimated at 1.4 kiloparsecs from assumptions about its intrinsic brightness. The absolute magnitude of −5 is calculated by comparison with R CrB variables in the Large Magellanic Cloud whose distances are known quite accurately. The luminosity is estimated from helium star models to be and the star has a radius around .
|
|
S Coronae Australis (S CrA), is a young binary star system estimated to be around 2 million years old located in the constellation Corona Australis. It is composed of a G-type main sequence star that is about as luminous as and just over twice as massive as the Sun, and a smaller K-type main sequence star that has around 50-60% of the Sun's luminosity and 1.3 times its mass. Both stars are T Tauri stars and both show evidence of having circumstellar disks. The system is around 140 parsecs distant.
|
|
Several "pancake volcanoes" called Carmenta Farra A pancake dome is an unusual type of lava dome found on the planet Venus. They are widely scattered on that planet and often form groups or clusters, though with smaller numbers of pancake domes in each group than is typical for the more common shield volcanos. They are commonly found near coronae and tesserae (large regions of highly deformed terrain, folded and fractured in two or three dimensions, believed to be unique to Venus) in the lowland plains. Pancake domes are between 10 and 100 times larger than volcanic domes formed on Earth.
|
|
Discovered in 1990, UW Coronae Borealis is a low-mass X-ray binary system composed of a star less massive than the Sun and a neutron star surrounded by an accretion disk that draws material from the companion star. It varies in brightness in an unusually complex manner: the two stars orbit each other every 111 minutes, yet there is another cycle of 112.6 minutes, which corresponds to the orbit of the disk around the degenerate star. The beat period of 5.5 days indicates the time the accretion disk—which is asymmetrical—takes to precess around the star.
|
|
Lying adjacent to the nebulosity is the globular cluster known as NGC 6723, which is actually in the neighbouring constellation of Sagittarius and is much much further away. Near Epsilon and Gamma Coronae Australis is Bernes 157, a dark nebula and star forming region. It is a large nebula, 55 by 18 arcminutes, that possesses several stars around magnitude 13. These stars have been dimmed by up to 8 magnitudes by its dust clouds. IC 1297 is a planetary nebula of apparent magnitude 10.7, which appears as a green-hued roundish object in higher-powered amateur instruments.
|
|
The office of coroner was formally established in England by Article 20 of the "Articles of Eyre" in September 1194 to "keep the pleas of the Crown" (Latin, custos placitorum coronae) from which the word "coroner" is derived. The eyre of 1194 was initiated under Hubert Walter's justiciarship to restore royal justice following the anarchy of Prince John's rebellion, begun when Richard I was detained in transit from the Third Crusade. Within two months, justices on eyre had visited every shire in England. Local knights were appointed coroners to record crown pleas to be presented to the justices.
|
|
William Axton Stokes (1814 - May 3, 1877) was an attorney born in Philadelphia, Pennsylvania who lived for a time in Greensburg, Pennsylvania where he served as legal counsel for the Pennsylvania Railroad Company. He went on to serve as an American Civil War major who contributed notes and references to an American edition of Mathew Hale's (1609–1676) Historia placitorum coronae (History of the pleas of the crown) published by R. H. Small of Philadelphia in 1847. Between January 1863 and August 1864, he owned The Republican, one of the first local newspapers in Greensburg, PA.
|
|
Observations from the Rossi X-ray Timing Explorer have been used as evidence for the existence of the frame-dragging effect predicted by the theory of general relativity. RXTE results have, as of late 2007, been used in more than 1400 scientific papers. In January 2006, it was announced that Rossi had been used to locate a candidate intermediate-mass black hole named M82 X-1. In February 2006, data from RXTE was used to prove that the diffuse background X-ray glow in our galaxy comes from innumerable, previously undetected white dwarfs and from other stars' coronae.
|
|
RY Sgr light curve Colonel Ernest Elliott Markwick first came across what became known as RY Sagittarii during searches for variable stars while posted in Gibraltar. He recorded it dimming from magnitude 7 in July 1893 to fainter than 11 by 23 October that year, and brightening to magnitude 6.4 by November 1894. Edward Charles Pickering wrote that it was a "remarkable object", and "nearly got away". The spectrum was first noted to be peculiar at the time, and by 1953 it was classified as a R Coronae Borealis variable, along with a handful of other stars.
|
|
BF Antliae is a Delta Scuti variable that varies by 0.01 of a magnitude. HR 4049, also known as AG Antliae, is an unusual hot variable ageing star of spectral type B9.5Ib-II. It is undergoing intense loss of mass and is a unique variable that does not belong to any class of known variable star, ranging between magnitudes 5.29 and 5.83 with a period of 429 days. It is around 6000 light-years away from Earth. UX Antliae is an R Coronae Borealis variable with a baseline apparent magnitude of around 11.85, with irregular dimmings down to below magnitude 18.0.
|
|
DY Persei is the larger of the two red stars in the center of this optical light image. DY Persei has a temperature around 3,000 K, but at a deep minimum its spectrum has been best modelled as the sum of two black body objects, one of 1,700 K typical of dusty circumstellar material and one of 2,400 K typical of the coolest giant stars. The size and luminosity of DY Persei, and other DY Persei and R Coronae Borealis stars, are very poorly known. The absolute magnitude is thought to be around −2.5, about 855 times brighter than the sun.
|
|
The fading is caused by condensation of carbon to soot, making the star fade in visible light while measurements in infrared light exhibit no real luminosity decrease. R Coronae Borealis variables are typically supergiant stars in the spectral classes F and G (by convention called "yellow"), with typical C2 and CN molecular bands, characteristic of yellow supergiants. RCB star atmospheres do however lack hydrogen by an abundance of 1 part per 1,000 down to 1 part per 1,000,000 relative to helium and other chemical elements, while the universal abundance of hydrogen is about 3 to 1 relative to helium.
|
|
The planet has few impact craters, demonstrating that the surface is relatively young, approximately 300–600 million years old. Venus has some unique surface features in addition to the impact craters, mountains, and valleys commonly found on rocky planets. Among these are flat-topped volcanic features called "farra", which look somewhat like pancakes and range in size from across, and from high; radial, star-like fracture systems called "novae"; features with both radial and concentric fractures resembling spider webs, known as "arachnoids"; and "coronae", circular rings of fractures sometimes surrounded by a depression. These features are volcanic in origin.
|
|
Images of ice water clouds over Tharsis taken by the ExoMars Trace Gas Orbiter, 2016 Spacecraft exploration over the last two decades has shown that volcanoes on other planets can take many unexpected forms.For specific examples, see coronae and arachnoids on the planet Venus or cryovolcanoes in the outer Solar System. Over the same time period, geologists were discovering that volcanoes on Earth are more structurally complex and dynamic than previously thought. Recent work has attempted to refine the definition of a volcano to incorporate geologic features of widely different shapes, sizes, and compositions throughout the Solar System.
|
|
The brighter component, Beta Coronae Borealis A, is a Rapidly oscillating Ap star, with a period of 16.2 minutes. Of spectral type A5V with a surface temperature of around 7980 K, it has around 2.09 times the mass of the Sun, 2.63 times its radius and 25.3 times its luminosity. The smaller star is a main sequence star with spectral type F2, a surface temperature of around 6750 K, around 1.4 times the mass of the Sun, 1.56 times its radius, and between 4 and 5 times its luminosity. The system is around 530 million years old.
|
|
Two distinct types of Cepheid variable have been identified, which have different period-luminosity relationships: Classical Cepheid variables are young massive population I stars; type II Cepheids are older population II stars with low masses, including W Virginis variables, BL Herculis variables and RV Tauri variables. The Classical Cepheids are more luminous than the type II Cepheids with the same period. R Coronae Borealis variables are often yellow supergiants, but their variability is produced by a different mechanism from the Cepheids. At irregular intervals, they become obscured by dust condensation around the star and their brightness drops dramatically.
|
|
A flaw in the inscriptions is that they put the entries concerning Laelianus' activities in the Parthian War under Lucius Verus. This war transpired over the years 161 through 166; Valarie Maxfield observes, "If he was aged twenty at the time of his tribunate he will have been nearly 60 when he accompanied Verus to the Parthian war, earning dona on the consular scale of four coronae and (probably) four hastae and four vexilla."Maxfield, The Dona Militaria of the Roman Army (Durham theses, Durham University, 1972), p. 37 During that war, Laelianus opposed Germanic tribes, the Sarmatians, Armenians and Parthia; for his efforts, Laelianus was awarded dona militaria.
|
|
The "Dividing Line" as giant stars evolve to become red giants also coincides with the Wind and Coronal Dividing Lines. To explain the drop in X-ray emission across these dividing lines, a number of models have been proposed: # low transition region densities, leading to low emission in coronae, # high-density wind extinction of coronal emission, # only cool coronal loops become stable, # changes in a magnetic field structure to that an open topology, leading to a decrease of magnetically confined plasma, or # changes in the magnetic dynamo character, leading to the disappearance of stellar fields leaving only small-scale, turbulence-generated fields among red giants.
|
|
XO-1 is a magnitude 11 yellow main-sequence star located approximately light-years away, of spectral type G1V with a mass and radius similar to the Sun. In 2006 the hot Jupiter exoplanet XO-1b was discovered orbiting XO-1 by the transit method using the XO Telescope. Roughly the size of Jupiter, it completes an orbit around its star every three days. The discovery of a Jupiter-sized planetary companion was announced in 1997 via analysis of the radial velocity of Rho Coronae Borealis, a yellow main sequence star and Solar analog of spectral type G0V, around 57 light-years distant from Earth.
|
|
More accurate measurement of data from the Hipparcos satellite subsequently showed it instead to be a low-mass star somewhere between 100 and 200 times the mass of Jupiter. Possible stable planetary orbits in the habitable zone were calculated for the binary star Eta Coronae Borealis, which is composed of two stars—yellow main sequence stars of spectral type G1V and G3V respectively—similar in mass and spectrum to the Sun. No planet has been found, but a brown dwarf companion about 63 times as massive as Jupiter with a spectral type of L8 was discovered at a distance of 3640 AU from the pair in 2001.
|
|
An extrasolar planet in a 39.8-day orbit around Rho Coronae Borealis was discovered in 1997 by observing the star's radial velocity variations. This detection method only gives a lower limit on the true mass of the companion. In 2001, preliminary Hipparcos astrometric satellite data indicated that the orbital inclination of the star's companion was 0.5°, nearly face-on, implying that its mass was as much as 115 times Jupiter's. A paper published in 2011 supported this claim using a new reduction of the astrometric data, with an updated mass value of 169.7 times Jupiter, with a 3σ confidence region 100.1 to 199.6 Jupiter masses.
|
|
The Roman army awarded a variety of individual decorations (dona) for valour to its legionaries. Hasta pura was a miniature gold spear; phalerae were large medal-like bronze or silver discs worn on the cuirass; armillae were bracelets worn on the wrist; and torques were worn round the neck, or on the cuirass. The highest awards were the coronae ("crowns"), of which the most prestigious was the corona civica, a crown made oak-leaves awarded for saving the life of a fellow Roman citizen in battle. The most valuable award was the corona muralis/vallaris, a crown made of gold awarded to the first man to scale an enemy wall/rampart.
|
|
The Ursa Major Moving Group was discovered in 1869 by Richard A. Proctor, who noticed that, except for Dubhe and Alkaid (Eta Ursae Majoris), the stars of the Big Dipper asterism all have proper motions heading towards a common point in Sagittarius. Thus, the Big Dipper, unlike most constellations or asterisms, is largely composed of related stars. Some of the brighter stream members include Alpha Coronae Borealis (α CrB or Alphecca or Gemma), Beta Aurigae (β Aur), Delta Aquarii (δ Aqr), Gamma Leporis (γ Lep) and Beta Serpentis (β Ser). More bright and moderately bright stars which are currently believed to be members of the group are listed below.
|
|
The radar images from the Magellan missions revealed that the terrestrial style of plate tectonics is not active on Venus and the surface appears to be immobile at the present time. Despite these surface observations, there are numerous surface features that indicate an actively convecting interior. The Soviet Venera landings revealed that the surface of Venus is essentially basaltic in composition based on geochemical measurements and morphology of volcanic flows. The surface of Venus is dominated by patterns of basaltic volcanism, and by compressional and extensional tectonic deformation, such as the highly deformed tesserae terrain and the pancake like volcano-tectonic features known as coronae.
|
|
FG Sagittae is the central star of the planetary nebula Henize 1-5. Since 1992 the star has exhibited fadings and recoveries similar to that of a R Coronae Borealis variable star; this behavior is emphasized by a hydrogen deficiency typical for this class of stars. It has been proposed that this star has undergone a "late thermal pulse" (LTP) of helium fusion after having left the asymptotic giant branch (AGB) to move towards the hottest end of the "white dwarf cooling track". This thermal pulse is believed to have revived this aged star to once again, for a short time, behave as an AGB star.
|
|
Stephanids are noted for their ocellar corona, a semicircular to circular set of projections around the middle ocellus, forming a "crown" on the head. Only stephanids and the similarly old Hymenoptera family Orussidae have ocellar coronae, and it is uncertain if they developed the structure separately or if a common ancestor of both developed it and it was then lost in all but the two families. Weakly developed grooves starting at the base of the antennae and extending past the eyes to the back of the head capsule are present. This feature is seen more developed in hymenopteran families in which the adults emerge from pupal chambers in wood.
|
|
Musser did his undergraduate studies in electrical engineering and mathematics at Brown University and his graduate studies in planetary science at Cornell University, where he was a National Science Foundation Graduate Fellow. His thesis work modeled mantle convection on Venus in order to explain broad plateaus, known as coronae, mapped by the Magellan orbiter. Musser served as editor of Mercury magazine and of the Universe in the Classroom tutorial series at the Astronomical Society of the Pacific, a science and science-education nonprofit based in San Francisco. A number of articles Musser solicited and edited have appeared in The Best American Science Writing and The Best American Science & Nature Writing anthologies.
|
|
Eta and PZ Telescopii are two young star systems with debris disks and brown dwarf companions. Telescopium hosts two unusual stars with very little hydrogen that are likely to be the result of two merged white dwarfs: PV Telescopii, also known as HD 168476, is a hot blue extreme helium star, while RS Telescopii is an R Coronae Borealis variable. RR Telescopii is a cataclysmic variable that brightened as a nova to magnitude 6 in 1948. Telescopium also hosts the first known visible star system with a black hole, QV Telescopii (HR 6819), which appears as a variable star with magnitude 5.32 to 5.39.
|
|
IC 2051 is a spiral galaxy located in Mensa (constellation). The Large Magellanic Cloud lies partially within Mensa's boundaries, although most of it lies in neighbouring Dorado. It is a satellite galaxy of the Milky Way, located at a distance of 163,000 light-years. Among its stars within Mensa are W Mensae, an unusual yellow-white supergiant that belongs to a rare class of star known as a R Coronae Borealis variable, HD 268835, a blue hypergiant that is girded by a vast circumstellar disk of dust, and R71, a luminous blue variable star that brightened in 2012 to over a million times as luminous as the Sun.
|
|
In 2009, after decades of attempting to resolve the GRXE, Mikhail Revnivtsev, his partner Sazonov and their colleges managed to resolve approximately 80% of the emissions over the course of 12 days using the Chandra X-ray observatory. During this time period a total of 473 sources of x-ray emission were detected in an area that is significantly smaller than the size of a Full Moon. This is one of the highest densities of x-ray sources ever seen in our Galaxy. Due to this amazing discovery it is now thought that about 80% of the emission comes from discrete sources such as white dwarfs and stars with active coronae.
|
|
The FK Com stars are giants of spectral type K with an unusually rapid rotation and signs of extreme activity. Their X-ray coronae are among the most luminous (LX ≥ 1032 erg·s−1 or 1025 W) and the hottest known with dominant temperatures up to 40 MK. However, the current popular hypothesis involves a merger of a close binary system in which the orbital angular momentum of the companion is transferred to the primary. Pollux is the brightest star in the constellation Gemini, despite its Beta designation, and the 17th brightest in the sky. Pollux is a giant orange K star that makes an interesting color contrast with its white "twin", Castor.
|
|
The Polish nobles saw the offer as an opportunity for increasing their privileges and avoiding Austrian influence, brought by Jadwiga's previous fiancé William, Duke of Austria. On 14 August 1385 in Kreva Castle, Jogaila confirmed his prenuptial promises in the Union of Krewo (Union of Kreva). The promises included the adoption of Christianity, repatriation of lands "stolen" from Poland by its neighbours, and terras suas Lithuaniae et Russiae Coronae Regni Poloniae perpetuo applicare, a clause interpreted by historians to mean anything from a personal union between Lithuania and Poland to a complete incorporation of Lithuania into Poland. The agreement at Kreva has been described both as far-sighted and as a desperate gamble.
|
|
The star is radiating 50 times the Sun's luminosity from its expanded photosphere at an effective temperature of 4,812 K. Omicron Coronae Borealis has one confirmed planet, believed to be, like HD 100655 b, one of the two least massive planets known around clump giants.Sato. Its m sin i is the least, but the true-mass depends on error and inclination. The planet was detected by measuring changes in radial velocity of the host star caused by gravitational perturbation of the orbiting object. It is orbiting with a period of 188 days, at a semimajor axis 83% of the mean separation between the Earth and the Sun, and an eccentricity of 0.19.
|
|
147–148 On the other hand, grains are seen to have recently formed in the vicinity of nearby stars, in nova and supernova ejecta, and in R Coronae Borealis variable stars which seem to eject discrete clouds containing both gas and dust. So mass loss from stars is unquestionably where the refractory cores of grains formed. Most dust in the Solar System is highly processed dust, recycled from the material out of which the Solar System formed and subsequently collected in the planetesimals, and leftover solid material such as comets and asteroids, and reformed in each of those bodies' collisional lifetimes. During the Solar System's formation history, the most abundant element was (and still is) H2.
|
|
Also, the cryovolcanic material responsible for the surfacing is too viscous to have been pure liquid water, but too fluid to have been solid water. Rather, it is believed to have been a viscous, lava-like mixture of water and ammonia, which freezes at , or perhaps ethanol. Miranda's observed hemisphere contains three giant 'racetrack'-like grooved structures called coronae, each at least wide and up to deep, named Arden, Elsinore and Inverness after locations in Shakespeare's plays. Inverness is lower in altitude than the surrounding terrain (though domes and ridges are of comparable elevation), while Elsinore is higher, The relative sparsity of craters on their surfaces means they overlay the earlier cratered terrain.
|
|
It is estimated to be 85 million years old, with the primary star expected to remain on the main sequence burning its core hydrogen for another 75 million years and the secondary around 500 million years. Both stars will cool and expand once their core hydrogen is exhausted, becoming red giants. The brighter component, Theta Coronae Borealis A, is a blue-white star that spins extremely rapidly—at a rate of around 393 km per second. This rapid spinning is thought to be the cause of a gaseous disk that surrounds the star: such stars are known as Be shell stars, recognizable because the gas radiates emission lines that give a characteristic pattern in the star's spectrum.
|
|
The constellation Corona Borealis as it can be seen by the naked eye Alpha Coronae Borealis (officially named Alphecca by the IAU, but sometimes also known as Gemma) appears as a blue-white star of magnitude 2.2. In fact, it is an Algol-type eclipsing binary that varies by 0.1 magnitude with a period of 17.4 days. The primary is a white main-sequence star of spectral type A0V that is 2.91 times the mass of the Sun () and 57 times as luminous (), and is surrounded by a debris disk out to a radius of around 60 astronomical units (AU). The secondary companion is a yellow main-sequence star of spectral type G5V that is a little smaller (0.9 times) the diameter of the Sun.
|
|
The constellation Corona Australis as it can be seen by the naked eye While not a bright constellation, Corona Australis is nonetheless distinctive due to its easily identifiable pattern of stars, which has been described as horseshoe- or oval-shaped. Though it has no stars brighter than 4th magnitude, it still has 21 stars visible to the unaided eye (brighter than magnitude 5.5). Nicolas Louis de Lacaille used the Greek letters Alpha through to Lambda to label the most prominent eleven stars in the constellation, designating two stars as Eta and omitting Iota altogether. Mu Coronae Australis, a yellow star of spectral type G5.5III and apparent magnitude 5.21, was labelled by Johann Elert Bode and retained by Benjamin Gould, who deemed it bright enough to warrant naming.
|
|
In collaboration with Jeremiah Ostriker (Columbia University), he developed the three-phase model of the interstellar medium, which has been widely used to organize and interpret observational data. His research on quasars has included development of the relativistic blast wave model for variability, introduction of reverberation mapping to analyze variable emission line profiles, the two-phase model for quasar emission line regions, and the development of the theory of coronae and winds from accretion disks. He has developed a self-regulated model for the structure and evolution of molecular clouds, and for the rate of star formation within these clouds. He established the Berkeley Astrophysical Fluid Dynamics Group with Richard Klein to develop the technique of adaptive mesh refinement for numerical simulations of astrophysical fluid dynamics.
|
|
Extreme helium stars form a sub-group within the broader category of hydrogen-deficient stars. The latter includes cool carbon stars like R Coronae Borealis variables, helium-rich spectral class O or B stars, population I Wolf–Rayet stars, AM CVn stars, white dwarfs of spectral type WC, and transition stars like PG 1159. The first known extreme helium star, HD 124448, was discovered in 1942 by Daniel M. Popper at the McDonald Observatory near Fort Davis, Texas, United States. This star displayed no lines of hydrogen in its spectrum, but strong helium lines as well as the presence of carbon and oxygen. The second, PV Telescopii, was discovered in 1952, and by 1996 a total of 25 candidates had been found.
|
|
This scenario is also accepted as the origin of the barium stars, which are also characterized as having strong spectral features of carbon molecules and of barium (an s-process element). Sometimes the stars whose excess carbon came from this mass transfer are called "extrinsic" carbon stars to distinguish them from the "intrinsic" AGB stars which produce the carbon internally. Many of these extrinsic carbon stars are not luminous or cool enough to have made their own carbon, which was a puzzle until their binary nature was discovered. The enigmatic hydrogen deficient carbon stars (HdC), belonging to the spectral class C-Hd, seems to have some relation to R Coronae Borealis variables (RCB), but are not variable themselves and lack a certain infrared radiation typical for RCB:s.
|
|
Unlike most coronae on the planet, which are about in diameter, Quetzalpetlatl Corona has a diameter of about . It is the third most massive corona after Artemis Corona and Heng-O Corona, and lies on the Lada Rise, with part of the corona intersecting the Ammavuro- Quetzalpetlatl belt in the northwestern region of Lada Terra. The corona consists of a raised inner region surrounded by the lower-lying "corona floor," with an elevated ridge about above the corona floor, as well as an outer "moat" of depressed terrain which is below the surrounding land. The corona is characterized by massive lava flows that cover almost of the Venusian surface, the largest lava flow extent seen on the planet to date.
|
|
Fotla Corona presents a variety of tectonic structures, including three farra of decreasing size from north to south (the largest in the north has a diameter of about 35 km) aligned along a line that intersects the corona in its part West. A rather complex fracture network is visible to the northeast, which among other volcanic structures are visible, probably due to effusion of lava through existing fractures, leading to the collapse of land located above. A set of volcanic domes aligned with the southern part of the circumference of the corona is visible, and a smooth land area in the center of the formation, perhaps the recent lava. These observations highlight the central role of volcanism in the genesis of coronae.
|
|
Many R Coronae Borealis variables, although not all, are yellow supergiants, but this variability is due to their unusual chemical composition rather than a physical instability. Further types of variable stars such as RV Tauri variables and PV Telescopii variables are often described as supergiants. RV Tau stars are frequently assigned spectral types with a supergiant luminosity class on account of their low surface gravity, and they are amongst the most luminous of the AGB and post-AGB stars, having masses similar to the sun; likewise, the even rarer PV Tel variables are often classified as supergiants, but have lower luminosities than supergiants and peculiar B[e] spectra extremely deficient in hydrogen. Possibly they are also post-AGB objects or "born-again" AGB stars.
|
|
About 80% of the planet consists of a mosaic of volcanic lava plains, dotted with more than a hundred large isolated shield volcanoes, and many hundreds of smaller volcanoes and volcanic constructs such as coronae. These are geological features believed to be almost unique to Venus: huge, ring-shaped structures 100-300 kilometers (60-180 mi) across and rising hundreds of meters above the surface. The only other place they have been discovered is on Uranus's moon Miranda. It is believed that they are formed when plumes of rising hot material in the mantle push the crust upwards into a dome shape, which then collapses in the centre as the molten lava cools and leaks out at the sides, leaving a crown-like structure: the corona.
|
|
The first feast in honour of the Crown of Thorns (Festum susceptionis coronae Domini) was instituted at Paris in 1239, when Louis IX of France brought there the relic of the Crown of Thorns, which was deposited later in the Royal Chapel, erected in 1241–48 to guard this and other relics of the Passion. The feast, observed on 11 August, though at first special to the Royal Chapel, was gradually observed throughout the north of France. In the following century another festival of the Holy Crown on 4 May was instituted and was celebrated along with the Feast of the Invention of the Cross in parts of Spain, Germany, and Scandinavia. It was later kept in Spanish dioceses and is observed by the Dominicans on 24 April.
|
|
A number of orbits were subsequently published using visual and speckle-interferometric observations, both alone and in conjunction with spectroscopic data.. In 1999, Söderhjelm published an orbit using speckle-interferometric data together with Hipparcos observations. Neubauer's 1944 work found a small variation in the radial velocity of Beta Coronae Borealis with a periodicity of 320 days, suggesting the presence of a third, lighter, body in the system. A 1999 study of the system by long- baseline infrared interferometry performed at Palomar Observatory found no evidence for this, and showed that any tertiary companion with this period must have mass 10 Jupiter masses or below. This study also found very weak evidence for the presence of a companion with a shorter, 21-day, period, but the data was insufficient to draw a positive conclusion.
|
|
Direct imaging with the Hubble Space Telescope shows extensive dust clouds out to a radius of around 2000 astronomical units from R Coronae Borealis, corresponding to a stream of fine dust (composed of grains about 5 nm in diameter) associated with the star's stellar wind, and coarser dust (composed of grains with a diameter of around 0.14 µm) ejected periodically. The obscuration appears to happen closer to the star as clouds of carbon condense at shock regions in an expanding front. "Puffs" of dust emitted from the star condense at about from the surface, and are visible as cometary knots when they lie to side of the star. There is also a shell about 4 pc wide containing dust at 25 K, which may be a fossil planetary nebula.
|
|
Before the first rocket missions, the corona could be observed only in white light during the eclipses, while in the last fifty years the solar corona has been photographed in the EUV and X-rays by many satellites (Pioneer 5, 6, 7, 8, 9, Helios, Skylab, SMM, NIXT, Yohkoh, SOHO, TRACE, Hinode). The emitting plasma is almost completely ionized and very light, its density is about 10−16 \- 10−14 g/cm3. Particles are so isolated that almost all the photons can leave the Sun's surface without interacting with the matter above the photosphere: in other words, the corona is transparent to the radiation and the emission of the plasma is optically- thin. The Sun's atmosphere is not the unique example of X-ray source, since hot plasmas are present wherever in the Universe: from stellar coronae to thin galactic halos.
|
|
Haisch was born in Stuttgart, Germany and earned a Ph.D. in Astronomy from the University of Wisconsin–Madison in 1975 and thereafter spent three years as a postdoctoral fellow at the Joint Institute for Laboratory Astrophysics at the University of Colorado in Boulder, Colorado. Haisch has worked at the Solar & Astrophysics Laboratory at Lockheed Martin in Palo Alto, California and served as deputy director of the Center for Extreme Ultraviolet Astrophysics Laboratory at the University of California, Berkeley. He has been a visiting scientist at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany and at the University of Utrecht in the Netherlands. His main research from the mid 1970s until the late 1990s was high energy astrophysics, and specifically the ultraviolet and X-ray emissions from coronae and flares on the Sun and other late-type stars.
|
|
Located south of Kochab and Pherkad towards Draco is RR Ursae Minoris, a red giant of spectral type M5III that is also a semiregular variable ranging from magnitude 4.44 to 4.85 over a period of 43.3 days. T Ursae Minoris is another red giant variable star that has undergone a dramatic change in status—from being a long period (Mira) variable ranging from magnitude 7.8 to 15 over 310–315 days to a semiregular variable. The star is thought to have undergone a shell helium flash—a point where the shell of helium around the star's core reaches a critical mass and ignites—marked by its abrupt change in variability in 1979. Z Ursae Minoris is a faint variable star that suddenly dropped 6 magnitudes in 1992 and was identified as one of a rare class of stars—R Coronae Borealis variables.
|
|
When the pulsation mechanisms of the δ Scuti stars and the similar but hotter Slowly pulsating B-type (SPB) stars were identified, it became apparent that γ Coronae Borealis and a handful of similar low amplitude variable stars such as γ Ursae Minoris and Maia fell between those two classes in a region with no known driver for pulsations. The Maia variable class was named for these stars. Ironically, Maia itself has been shown not to be variable, and a number of other reported members of the class have been shown to be variables of other types, so the Maia variables appear to be very rare if they are even a real variable class. However, satellite observations have discovered a number of small-amplitude variables between the SPB and δ Scuti instability regions as well as a number of candidates in the open clusters NGC 3766 and NGC 1893.
|
|
V605 Aquilae, in the constellation Aquila, is the variable central star of the planetary nebula Abell 58. It is a highly unusual hydrogen-deficient carbon- rich star. V605 Aquilae was first recorded as a nova in 1919, but it turned out to be a very unusual variable. It was measured to be magnitude 10.4 at its peak. Investigation of prior photographs showed that it was magnitude 15 or fainter until 1918, when it brightened to 12th magnitude. It stayed at 11th magnitude or brighter for over a year, before fading from sight. It then brightened to 12th magnitude in late 1921 and again in 1923, before disappearing. The spectral type at the time of the outbursts was R0, a cool hydrogen-deficient carbon star similar to some R Coronae Borealis (RCB) stars. V605 Aquilae was subsequently detected several times at magnitudes 18–20, but these are likely to have been detections only of a small knot of nebulosity surrounding the position of the star.
|
|
Close-up of Verona Rupes, a large fault scarp on Miranda possibly high, taken by Voyager 2 in January 1986 Close-up of the ring of concentric fault scarps around Elsinore Corona The three coronae imaged on Miranda by Voyager 2 The fault scarps around Elsinore (top right) and the chevrons of Inverness Corona (bottom left) Due to Uranus's near-sideways orientation, only Miranda's southern hemisphere was visible to Voyager 2 when it arrived. The observed surface has patchwork regions of broken terrain, indicating intense geological activity in Miranda's past, and is criss-crossed by huge canyons, believed to be the result of extensional tectonics; as liquid water froze beneath the surface, it expanded, causing the surface ice to split, creating graben. The canyons are hundreds of kilometers long and tens of kilometers wide. Miranda also has the largest-known cliff in the Solar System, Verona Rupes, which has a height of .
|
|
Two main models for carbon dust formation near the R Coronae Borealis stars have been proposed, one model that presumes the dust forms at a distance of 20 star radii from the center of the star, and one model that presumes that the dust forms in the photosphere of the star. The rationale for the 20 radii formation is that the carbon condensation temperature is 1,500 K, while the photospheric dust model was formulated by the 20 radii model's failure to explain the fast decline of the RCBs' light curves just before reaching minimum. The 20 radii model requires a large and thereby long-time buildup of the obstructing dust cloud, making the fast light decline hard to comprehend. The alternate theory of photospheric buildup of carbon dust in a 4,500–6,500 K temperature environment could be explained by condensations in the low pressure parts of shock fronts – being detected in the atmosphere of RY Sagittarii – a condensation that causes local runaway cooling, allowing carbon dust to form.
|
|
The Empress donated these lands and possessions to Croatia – Hungary as a compensation since many of their lands were put under the direct imperial administration as the osterreichische Militargrenze (Military Frontier) against the Turks, exclusively for defensive purposes. The corpus separatum Maria Theresa, with her sovereign decision from October the 2nd 1776, gave up the possession of Fiume, that so far belonged to the Habsburgs, and give it to the Hungarian kingdom, with a view of fostering its trade. Since Hungary proper was distant some 500 km, according to the act, understandably, the city was annexed to Croatia whose territory began right beyond the city walls. Although Croatia, as a kingdom, was united with Hungary and together they formed the "Lands of the Holy Crown of St Stephen", the Fiumani protested, and with support of the Hungarian Vice Regency Council, two and a half years later, Maria Theresa (as Queen of Hungary) enacted the royal rescript on April, the 23rd 1779, with whom Fiume was annexed to Hungary directly as a corpus separatum adnexum sacra hungaricae coronae.
|
|
Hostettler (2002) p.187 Hale proposed the creation of county courts, and also drew a strong distinction between written laws, such as statutes, and customary, unwritten laws.Hostettler (2002) p.188 He also argued that the common law was subject to Parliament, far before the confirmation of Parliamentary supremacy, and that the law should protect the rights and civil liberties of the King's subjects.Hostettler (2002) p.189 He also argued for the confirmation of trial by jury, which he described as "the best mode of trial in the world", while the 13th chapter divided the law into the laws of persons and of property, and dealt with the rights, wrongs and remedies recognised by the law at the time.Hostettler (2002) p.192 William Holdsworth, himself considered one of the greatest common law historians, described it as "the ablest introductory sketch of a history of English law that appeared till the publication of Pollock and Maitland's volumes in 1895".Hostettler (2002) p.193 The title page of volume I of the first edition of Historia Placitorum Coronae (1736) The Historia is perhaps Hale's most famous work.
|
|
The title page of volume I of the first edition of Historia Placitorum Coronae (1736) Historia Placitorum Coronæ or The History of the Pleas of the Crown is an influential treatise on the criminal law of England, written by Sir Matthew Hale and published posthumously with notes by Sollom Emlyn by E. and R. Nutt, and R. Gosling (the assigns of Edward Sayer), for F. Gyles, T. Woodward, and C. Davis in 1736.. The book was published despite an instruction in Hale's will that none of his manuscripts was to be printed after his death unless he had ordered the publication during his lifetime.. This was defended by Emlyn on the basis that it was a work of enormous importance; that he appeared to have revoked this instruction in a codicil; and that, in any event, it was obvious that he had intended to publish it. He further observed that the order was the result of fear that the text would be altered or abridged. The book is divided into two parts. The first part deals with substantive law and the second part deals with procedure.
|
|
The European X-ray Observatory Satellite (EXOSAT), originally named HELOS, was an X-ray telescope operational from May 1983 until April 1986 and in that time made 1780 observations in the X-ray band of most classes of astronomical object including active galactic nuclei, stellar coronae, cataclysmic variables, white dwarfs, X-ray binaries, clusters of galaxies, and supernova remnants. This European Space Agency (ESA) satellite for direct-pointing and lunar-occultation observation of X-ray sources beyond the solar system was launched into a highly eccentric orbit (apogee 200,000 km, perigee 500 km) almost perpendicular to that of the moon on 26 May 1983. The instrumentation includes two low-energy imaging telescopes (LEIT) with Wolter I X-ray optics (for the 0.04–2 keV energy range), a medium-energy experiment using Ar/CO2 and Xe/CO2 detectors (for 1.5–50 keV), a Xe/He gas scintillation spectrometer (GSPC) (covering 2–80 keV), and a reprogrammable onboard data-processing computer. Exosat was capable of observing an object (in the direct-pointing mode) for up to 80 hours and of locating sources to within at least 10 arcsec with the LEIT and about 2 arcsec with GSPC.
|
|