Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Ophiuchus |
Right ascension | 16h 59m 30.375s [1] |
Declination | −12° 53′ 27.14″ [1] |
Apparent magnitude (V) | 4.3 - 13.5 [2] |
Characteristics | |
Variable type | classical nova [2] |
Astrometry | |
Distance | 823+20 −17 [3] pc |
Other designations | |
Database references | |
SIMBAD | data |
V841 Ophiuchi (Nova Ophiuchi 1848) was a bright nova discovered by John Russell Hind on 27 April 1848. It was the first object of its type discovered since 1670. [5] At the time of its discovery, it had an apparent magnitude of 5.6, [4] but may have reached magnitude 2 at its peak, making it easily visible to the naked eye. Near peak brightness it was described as "bright red" or "scarlet", probably due to Hα line emission. [5] Its brightness is currently varying slowly around magnitude 13.5. [6] The area of the sky surrounding this nova had been examined frequently by astronomers prior to the nova's discovery, because it was near the reported location of "52 Serpentis", a star John Flamsteed had included in his catalogue with erroneous coordinates. [7]
Like all cataclysmic variable (CV) stars, novae are short-period binary stars with a "donor" star transferring material to a white dwarf. In the case of V841 Ophiuchi, the orbital period is 14.43 hours, which is unusually long for a CV; the vast majority of such systems have periods below 10 hours. [8] Peters and Thorstensen derive an orbital inclination of 30°±10° with respect to our line of sight which, combined with the relatively large separation implied by the orbital period, would explain why V841 Ophiuchi is not an eclipsing binary. They also found that the donor star is somewhat cooler than the Sun, likely early K-type or late G-type. [9]
Modern observations during a 30-year time interval show that V841 Ophiuchi undergoes regular brightness variations with a period of 3.4 years, and an amplitude of about 0.3 magnitudes, which may be due to oscillations in the donor star similar to our Sun's solar cycle. [10] Non-periodic "flickering" brightness variations have been reported, on timescales as short as 100 seconds. [11]
V603 Aquilae was a bright nova first observed in the constellation Aquila in 1918. It was the brightest "new star" to appear in the sky since Kepler's Supernova in 1604. Like all novae, it is a binary system, comprising a white dwarf and donor low-mass star in close orbit to the point of being only semidetached. The white dwarf sucks matter off its companion, which has filled its Roche lobe, onto its accretion disk and surface until the excess material is blown off in a thermonuclear event. This material then forms an expanding shell, which eventually thins out and disappears.
V1500 Cygni or Nova Cygni 1975 was a bright nova occurring in 1975 in the constellation Cygnus. It had the second highest intrinsic brightness of any nova of the 20th century, exceeded only by CP Puppis in 1942.
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.
V849 Ophiuchi or Nova Ophiuchi 1919 was a nova that erupted in 1919, in the constellation Ophiuchus, and reached a blue band brightness of magnitude 7.2. Joanna C. S. Mackie discovered the star while she was examining Harvard College Observatory photographic plates. The earliest plate it was visible on was exposed on August 20, 1919, when the star was at magnitude 9.4. It reached magnitude 7.5 on September 13 of that year. In its quiescent state it has a visual magnitude of about 18.8. V849 Ophiuchi is classified as a "slow nova"; it took six months for it to fade by three magnitudes.
V446 Herculis was a nova in the constellation Hercules in 1960. It reached magnitude 2.8. The nova was first observed by Olaf Hassel in the early morning hours of 7 March 1960, when it was a 5th magnitude star. Pre-discovery photographs showed that it was about three days past peak brightness, and had faded by 2 magnitudes during that time. The star was so near the border between the constellations of Hercules and Aquila that accurate measurements of its position were needed to determine which constellation contained it.
V533 Herculis was a nova visible to the naked eye, which occurred in 1963 in the constellation of Hercules.
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.
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.
DM Lyrae is a dwarf nova in the constellation Lyra. This binary system is composed of a primary star of unknown type, and a white dwarf companion. It erupted in 1928 and 1996 and reached about magnitude 13.
U Geminorum, in the constellation Gemini, is an archetypal example of a dwarf nova. The binary star system consists of a white dwarf closely orbiting a red dwarf. Every few months it undergoes an outburst that greatly increases its brightness. The dwarf nova class of variable stars are often referred to as U Geminorum variables after this star.
SS Cygni is a variable star in the northern constellation Cygnus. It is the prototype of the subclass of dwarf novae that show only normal eruptions. It typically rises from 12th magnitude to 8th magnitude for 1–2 days every 7 or 8 weeks. The northerly declination of SS Cygni makes the star almost circumpolar from European and North American latitudes, allowing a large proportion of the world's amateur astronomers to monitor its behavior. Furthermore, since the star lies against the rich backdrop of the Milky Way band, the telescope field of view around SS Cygni contains an abundance of useful brightness comparison stars.
CE Gruis is a faint binary star system in the constellation Grus. It is a variable star, with a B-band brightness that ranges from a peak magnitude of 17.4 down to a minimum of 19.5 over a period of 108.6 minutes. The system is composed of a white dwarf and donor star, locked into a close, synchronous orbit. In such systems, known as polars, material from the donor star does not form an accretion disc around the white dwarf because of its intense magnetic field, but rather streams directly onto it along columns.
ZZ Boötis is a star system in the constellation Boötes. It varies from magnitude 6.79 to 7.44 over five days. Based on its parallax, measured by the Gaia spacecraft, it is about 350 light-years away.
Q Cygni, is a star located in the constellation Cygnus. It is also known as Nova Cygni 1876, and has the designation NGC 7114, and HR 8296. Nova Cygni is located in the northwestern portion of Cygnus along the border with Lacerta.
BV Centauri is a cataclysmic variable binary star in the constellation Centaurus. It is a dwarf nova, and undergoes rapid increases in brightness that are recurrent with a mean period of 150 days. This period seems to have increased in the last few decades. During quiescence, its visual apparent magnitude is about 13, with variations of a few tenths of magnitude over an orbit due to differences in the star's visible surface area, brightening to a maximum magnitude of 10.7 during outbursts. From its luminosity, it is estimated that the system is about 500 parsecs (1,600 ly) away from Earth. A Gaia parallax of 2.81 mas has been measured, corresponding to about 360 pc.
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.
V392 Persei, also known as Nova Persei 2018, is a bright nova in the constellation Perseus discovered on April 29, 2018. It was previously known as a dwarf nova.
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.
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.