Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Delphinus |
Right ascension | 20h 42m 20.347s [1] |
Declination | +19° 09′ 39.30″ [1] |
Apparent magnitude (V) | 3.5 – 12.0 [2] (var.) |
Characteristics | |
Variable type | Classical Nova [3] |
Astrometry | |
Distance | 932 ± 31 [4] pc |
Other designations | |
Nova Delphini 1967, HR Del, AAVSO 2037+18, 2MASS J20422035+1909394. Gaia DR2 1813953083546374144 [5] | |
Database references | |
SIMBAD | data |
HR Delphini, also known as Nova Delphini 1967, was a nova which appeared in the constellation Delphinus in 1967. It was discovered by George Alcock at 22:35 UT on 8 July 1967, after searching the sky for over 800 hours with binoculars. At the time of discovery it had an apparent magnitude of 5.0. It reached a peak brightness of magnitude 3.5 on 13 December 1967, making it easily visible to the naked eye around that time. [6] [7] Pre-outburst photographs taken with the Samuel Oschin telescope showed it as a ~12th magnitude star which might have been variable. [8]
HR Delphini was discovered 158 days before it reached peak brightness, and its light curve around the peak was very well observed. [7] It had a very slow rise to maximum brightness, when compared to other classical novae. [3] It took 230 days for HR Delphini to fade from its peak by 3 magnitudes, which makes it a "slow" nova. [2] Its decline from peak brightness showed several brief outbursts, leading to its light curve being classified as type "J" (for "jitters"). [9]
In June 1970, HR Delphini was detected in 3.7 cm and 11.1 cm radio wavelengths with the Green Bank Interferometer, and at 1.95 cm with the Green Bank 140 foot telescope. [10]
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. In the case of HR Delphini, the orbital period of the binary pair is 5.14 hours. The mass of the white dwarf is estimated to be between 0.6 and 0.75 M☉ and the donor star is believed to be a main sequence star with a mass between 0.52 and 0.58 M☉ with a spectral type in the range of K5V to M1V. [11]
HR Delphini is surrounded by a bipolar nova remnant emission nebula, visible in Hα, Hβ as well as forbidden lines of oxygen and nitrogen. It is roughly ellipsoidal, with a central ring around the equatorial region. [12] It had a size of 3.7 × 2.5 arc seconds when it was discovered in 1981, and had expanded to roughly 8.5 × 6.1 arc seconds when it was observed with the Hubble Space Telescope in 1997. [13]
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.
DQ Herculis, or Nova Herculis 1934, was a slow, bright nova occurring in the northern constellation of Hercules in December 1934. This cataclysmic variable star was discovered on 13 December 1934 by J. P. M. Prentice from Stowmarket, Suffolk. It reached peak brightness on 22 December 1934 with an apparent magnitude of 1.5. The nova remained visible to the naked eye for several months.
V382 Velorum, also known as Nova Velorum 1999, was a bright nova which occurred in 1999 in the southern constellation Vela. V382 Velorum reached a brightness of 2.6 magnitude, making it easily visible to the naked eye. It was discovered by Peter Williams of Heathcote, New South Wales, Australia at 09:30 UT on 22 May 1999. Later that same day it was discovered independently at 10:49 UT by Alan C. Gilmore at Mount John University Observatory in New Zealand.
T Coronae Borealis, 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.
T Aurigae was a nova, which lit up in the constellation Auriga in 1891. Thomas David Anderson, an amateur astronomer in Edinburgh, reported that he was "almost certain" he saw the nova at 02:00 UT on 24 January 1892, when it was slightly brighter than χ Aurigae. He mistook the star for 26 Aurigae, although he noted to himself that it seemed brighter than he remembered it being. He saw it twice more during the following week. On 31 January 1892 he realized his mistake, and wrote a note to Ralph Copeland reporting his discovery. Professor Copeland immediately reported the discovery via telegram to William Huggins, who made the first spectroscopic observations of T Aurigae on 2 February 1892, when the star was a magnitude 4.5 object. T Aurigae was the first nova to be observed spectroscopically.
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.
DN Geminorum or Nova Geminorum 1912 was a classical nova which lit up in 1912 in the constellation Gemini. It was discovered by Norwegian variable star observer Sigurd Einbu on March 12, 1912 before reaching peak brightness, which allowed early-stage spectra to be collected by Yerkes Observatory. The nova reached a maximum brightness of around 3.5 mag before declining, which means it was visible to the naked eye. Its brightness decreased over the following 36 days by 3 magnitudes as it gradually faded from sight. The light curve saw two maxima a few months after the outburst, along with strong oscillations. Today its brightness is visual magnitude 15.5.
CP Lacertae was a nova, which lit up on June 18, 1936 in the constellation Lacerta. It was discovered independently by several observers including Leslie Peltier in the US, E. Loreta in Italy, and Kazuaki Gomi, a Japanese barber who discovered the nova during the 19 June 1936 total solar eclipse.
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.
HR Lyrae or Nova Lyrae 1919 was a nova which occurred in the constellation Lyra in 1919. Its discovery was announced by Johanna C. Mackie on 6 December 1919. She discovered it while examining photographic plates taken at the Harvard College Observatory. The bulletin announcing the discovery states "Between December 4 and 6 it rose rapidly from the sixteenth magnitude or fainter, to a maximum of about 6.5". It was the first nova ever reported in Lyra, and Mackie was awarded the AAVSO gold medal for her discovery. Its peak magnitude of 6.5 implies that it might have been visible to the naked eye, under ideal conditions.
NQ Vulpeculae also known as Nova Vulpeculae 1976, was a nova that appeared in the constellation Vulpecula in 1976. It was discovered visually at 18:20 UT on October 21, 1976 by English amateur astronomer George Alcock. Its apparent magnitude at the time of discovery was 6.5 It reached its maximum brightness of magnitude 6.0 thirteen days after its discovery, at which point it may have been faintly visible to the naked eye. A few days after maximum brightness, it had faded to magnitude 8.3.
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.
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.
V842 Centauri, also known as Nova Centauri 1986, was a nova which occurred in 1986 in the constellation Centaurus. It was discovered by Robert H. McNaught of Siding Spring Observatory in Australia, on 22 November 1986. At the time of its discovery, it had an apparent magnitude of 5.6. It reached a peak magnitude of 4.6 one and a half days later, making it easily visible to the naked eye.
V337 Carinae is a K-type bright giant star in the constellation of Carina. It is an irregular variable and has an apparent visual magnitude which varies between 3.36 and 3.44.
V339 Delphini or Nova Delphini 2013 (PNV J20233073+2046041) is a bright nova star in the constellation Delphinus. It was discovered on 14 August 2013 by amateur astronomer Koichi Itagaki in Japan and confirmed by the Liverpool Telescope on La Palma. The nova appeared with a magnitude 6.8 when it was discovered and peaked at magnitude 4.3 on 16 August 2013. A nova is produced by the fusion of accumulated material on the white dwarf nova progenitor acquired from its companion star. The nova system is thus a binary star, and a classical nova. The white dwarf is a carbon-oxygen white dwarf, with an estimated mass of 1.04±0.02 M☉. There is not yet a consensus about what the binay's orbital period is; estimates range from 3.15 hours to 6.43 hours.
KT Eridani was a bright nova in the constellation Eridanus that produced an outburst in 2009. It was the first classical nova ever detected in that constellation. The nova was discovered at 12:52 UT on 25 November 2009 by K. Itagaki at Yamagata, Japan with a 21 cm patrol telescope. At the time of its discovery, it was a magnitude 8.1 object. The discovery occurred after the nova's peak brightness, but the All Sky Automated Survey system had detected the nova on three earlier occasions, allowing a more complete light curve to be produced. The peak magnitude, 5.4, was seen at 15:10 UT on 14 November 2009.
RW Ursae Minoris is a cataclysmic variable star system that flared up as a nova in the constellation Ursa Minor in 1956.
V1309 Scorpii is a contact binary that merged into a single star in 2008 in a process known as a luminous red nova. It was the first star to provide conclusive evidence that contact binary systems end their evolution in a stellar merger. Its similarities to V838 Monocerotis and V4332 Sagittarii allowed scientists to identify these stars as merged contact binaries as well.
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.