A light curve for OY Arae. The main plot (from data published by Walker and Shapley) [1] shows the 1910 eruption, and the inset plot (adapted from Zhao and McClintock) [2] shows the eclipse light curve measured in 1995. | |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Ara |
Right ascension | 16h 40m 50.456s [3] |
Declination | −52° 25′ 47.98″ [3] |
Apparent magnitude (V) | 18.7 [4] |
Characteristics | |
Apparent magnitude (B) | 6.0 –18.6 [5] |
B−V color index | −0.15 [6] |
Variable type | Nova + eclipsing [5] |
Astrometry | |
Proper motion (μ) | RA: −3.689 [3] mas/yr Dec.: −3.182 [3] mas/yr |
Parallax (π) | 0.2676 ± 0.0714 mas [3] |
Distance | approx. 12,000 ly (approx. 3,700 pc) |
Absolute magnitude (MV) | −6.7 (at peak) 4.6 (quiescent) [7] |
Orbit | |
Period (P) | 3.72936 h [8] |
Semi-major axis (a) | 1.28±0.04 R☉ [2] |
Inclination (i) | 74.3±1.2 [2] ° |
Details | |
white dwarf | |
Mass | 0.82±0.12 [2] M☉ |
donor | |
Mass | 0.34±0.01 [2] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
OY Arae, also known as Nova Arae 1910, is a nova in the constellation Ara. It was discovered by Williamina Fleming on a Harvard Observatory photographic plate taken on April 4, 1910. At that time it had a magnitude of 6.0, making it faintly visible to the naked eye under ideal observing conditions. Examination of earlier plates showed that before the outburst it was a magnitude 17.5 object, and by March 19, 1910, it had reached magnitude 12. [9] [2]
OY Arae is considered to be a moderately fast nova, because it faded by 3 magnitudes during the 83 days after discovery. [10] [9] The light curve shows a secondary maximum in June 1910. The first spectrum of the nova was obtained on July 5, 1910, and resembled that of a gaseous nebula. [11] An optical identification of the quiescent nova was made in 1994, and spectra taken at that time showed strong Balmer lines in emission atop a blue continuum. [2]
All novae are binary stars, with a "donor" star orbiting a white dwarf. The two stars are so close to each other that material is transferred from the donor to the white dwarf. Because the distance between the two stars is comparable to the radius of the donor star, novae are often eclipsing binaries, and OY Arae does show eclipses. The primary eclipse, in which the donor star eclipses the white dwarf and its accretion disk, are about 2 magnitudes deep and last less than 30 minutes. The orbital period is 3.73118 hours. The mass of the white dwarf is 0.82±0.12 M☉, and the mass of the donor star is 0.34±0.01 M☉. The two stars are separated by 1.28±0.04 R☉. [2]
Most of the luminosity of the system is produced by the disk of material being stripped from the donor star. This is estimated to be 7 magnitudes brighter than the donor star itself, with the white dwarf being even fainter. The absolute magnitude of the system is given as +4.6, but this value is distorted by the shape of the disk, seen nearly edge-on. A mean absolute magnitude adjusted for viewing angle is +3.6. [2]
GK Persei was a bright nova first observed on Earth in 1901. It was discovered by Thomas David Anderson, an Edinburgh clergyman, at 02:40 UT on 22 February 1901 when it was at magnitude 2.7. It reached a maximum magnitude of 0.2, the brightest nova of modern times until Nova Aquilae 1918. After fading into obscurity at about magnitude 12 to 13 during the early 20th century, GK Persei began displaying infrequent outbursts of 2 to 3 magnitudes. Since about 1980, these outbursts have become quite regular, typically lasting about two months and occurring about every three years. Thus, GK Persei seems to have changed from a classical nova like Nova Aquilae 1918 to something resembling a typical dwarf nova-type cataclysmic variable star.
DI Lacertae or Nova Lacertae 1910 was a nova in constellation Lacerta which appeared in 1910. It was discovered by Thomas Henry Espinell Compton Espin at Wolsingham Observatory on 30 Dec 1910, at which time it was an 8th magnitude object. Subsequent examination of pre-discovery photographic plates showed that the outburst occurred sometime between 17 November 1910 and 23 November 1910. It reached a peak brightness of magnitude 4.6 on 26 November 1910, making it visible to the naked eye. Before the nova event DI Lacertae was a 14th magnitude star, and by 1950 it had returned to 14th magnitude.
BT Monocerotis was a nova, which lit up in the constellation Monoceros in 1939. It was discovered on a spectral plate by Fred L. Whipple on December 23, 1939. BT Monocerotis is believed to have reached mag 4.5, which would have made it visible to the naked eye, but that value is an extrapolation; the nova was not observed at peak brightness Its brightness decreased after the outbreak by 3 magnitudes in 182 days, making it a "slow nova". The light curve for the eruption had a long plateau period.
DK Lacertae was a nova, which lit up in the constellation Lacerta in 1950. The nova was discovered by Charles Bertaud of the Paris Observatory on a photographic plate taken on 23 January 1950. At the time of its discovery, it had an apparent magnitude of 6.1. DK Lacertae reached peak magnitude 5.0, making it easily visible to the naked eye.
V838 Herculis, also known as Nova Herculis 1991, was a nova which occurred in the constellation Hercules in 1991. It was discovered by George Alcock of Yaxley, Cambridgeshire, England at 4:35 UT on the morning of 25 March 1991. He found it with 10×50 binoculars, and on that morning its apparent visual magnitude was 5. Palomar Sky Survey plates showed that before the outburst, the star was at photographic magnitude 20.6 and 18.25.
V1494 Aquilae or Nova Aquilae 1999 b was a nova which occurred during 1999 in the constellation Aquila and reached a brightness of magnitude 3.9 on 2 December 1999. making it easily visible to the naked eye. The nova was discovered with 14×100 binoculars by Alfredo Pereira of Cabo da Roca, Portugal at 18:50 UT on 1 December 1999, when it had a visual magnitude of 6.0.
QU Vulpeculae, also known as Nova Vulpeculae 1984 Number 2, was the second nova which occurred in 1984 in the constellation Vulpecula. It was discovered by Peter Collins, an amateur astronomer from Cardiff, California at 22:08 UT on 22 December 1984. At the time of its discovery, the nova's apparent magnitude was 6.8. By the next night, Collins reported its brightness had increased to magnitude 5.6, making it visible to the naked eye.
V1059 Sagittarii was a nova, which lit up in 1898 in the constellation Sagittarius. The star reached apparent magnitude 4.5, making it easily visible to the naked eye. It was discovered on 8 March 1898, by Williamina Fleming on a photographic plate taken at the Harvard College Observatory. The discovery plate was an objective prism plate, part of the Henry Draper Memorial Photographs, and Ms Fleming identified it as a nova based on its spectral characteristics.
An AM Canum Venaticorum star, is a rare type of cataclysmic variable star named after their type star, AM Canum Venaticorum. In these hot blue binary variables, a white dwarf accretes hydrogen-poor matter from a compact companion star.
RX Andromedae is a variable star in the constellation of Andromeda. Although it is classified as a dwarf nova of the Z Camelopardalis (UGZ) type, it has shown low-luminosity periods typical of VY Sculptoris stars. However, for most of the time it varies from an apparent visual magnitude of 15.1 at minimum brightness to a magnitude of 10.2 at maximum brightness, with a period of approximately 13 days.
SU Ursae Majoris, or SU UMa, is a close binary star in the northern circumpolar constellation of Ursa Major. It is a periodic cataclysmic variable that varies in magnitude from a peak of 10.8 down to a base of 14.96. The distance to this system, as determined from its annual parallax shift of 4.53 mas, is 719 light-years. It is moving further from the Earth with a heliocentric radial velocity of +27 km/s.
PX Andromedae is an eclipsing cataclysmic variable star in the constellation Andromeda. It has been classified as a SW Sextantis variable, and its apparent visual magnitude varies between 14.04 and 17.
V455 Andromedae is a dwarf nova in the constellation Andromeda. It has a typical apparent visual magnitude of 16.5, but reached a magnitude of 8.5 during the only observed outburst.
V630 Sagittarii was a nova visible to the naked eye in 1936. It was discovered on 3 October 1936 by Shigeki Okabayashi of Kobe, Japan when it had an apparent magnitude of 4.5.
V728 Scorpii, also known as Nova Scorpii 1862, was a nova that occurred in the constellation of Scorpius. It was discovered on 4 October 1862 by John Tebbutt, an astronomer living in New South Wales, Australia, while he was observing a comet. He reported that the star was in the constellation Ara. At the time of its discovery, the nova had an apparent magnitude of 5, making it visible to the unaided eye. Nine days later it had faded to below 11th magnitude, indicating that it was a very fast nova.
V Persei, also known as Nova Persei 1887 was discovered by Williamina Fleming on a Harvard College Observatory objective-prism photograph taken on 3 November 1887. It is believed to be the first nova whose spectrum was recorded. The nova had an apparent magnitude of 9.2 at the time of discovery. Judging from the consistency of the nova's brightness after discovery, and details of the spectral lines seen, McLaughlin estimated that the nova was five or six months past peak brightness at the time of its discovery, and at its peak it was almost certainly at least as bright as 4th magnitude. So V Persei was probably visible to the naked eye, though there is no record that anyone actually noticed it when that was possible. It is currently an 18th magnitude object.
V368 Aquilae, also known as Nova Aquilae 1936 no. 2 was the second nova which occurred in the constellation of Aquila during 1936. It was discovered on a photographic plate by Nils Tamm at Kvistaberg Observatory on 7 October 1936. At the time of discovery it was at photographic magnitude 7, and was already fading. Pre-discovery photographs showed that peak brightness occurred around 25 September 1936, at which time it had reached apparent magnitude 5.0, making it visible to the naked eye. The nova was described as being fiery red due to strong Hα emission, and for a time could be seen with binoculars simultaneously with V356 Aquilae, another nova which Nill Tamm had discovered a month earlier.
QZ Aurigae, also known as Nova Aurigae 1964, was a nova which occurred in the constellation Auriga during 1964. It was discovered by Nicholas Sanduleak on an objective prism photographic plate taken at the Warner and Swasey Observatory on 4 November 1964. Examination of pre-discovery plates from Sonneberg Observatory showed that the eruption occurred in early February 1964, and it had a photographic magnitude of 6.0 on 14 February 1964. Its brightness declined in images taken after the 14th, suggesting that its peak brightness was above 6.0. It was probably visible to the naked eye for a short time.
GI Monocerotis, also known as Nova Monocerotis 1918, was a nova that erupted in the constellation Monoceros during 1918. It was discovered by Max Wolf on a photographic plate taken at the Heidelberg Observatory on 4 February 1918. At the time of its discovery, it had a photographic magnitude of 8.5, and had already passed its peak brightness. A search of plates taken at the Harvard College Observatory showed that it had a photographic magnitude of 5.4 on 1 January 1918, so it would have been visible to the naked eye around that time. By March 1918 it had dropped to ninth or tenth magnitude. By November 1920 it was a little fainter than 15th magnitude.
V1370 Aquilae, also known as Nova Aquilae 1982, is a nova that appeared in the constellation Aquila during 1982. It was discovered by Minoru Honda of Kurashiki, Japan at 20:30 UT on 27 January 1982. At that time the Sun had moved just far enough from Aquila to allow the nova to be seen in the morning sky. Although it was discovered photographically, its apparent magnitude was 6–7, making it potentially visible to the naked eye under ideal conditions. A possible magnitude 20 progenitor was located on the Palomar Sky Survey prints. Spectra of the object were taken in February 1982 at Asiago Astrophysical Observatory, which confirmed that it is a nova.