V1500 Cygni

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V1500 Cygni
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cygnus
Right ascension  21h 11m 36.6s
Declination +48° 09′ 02.1″
Apparent magnitude (V) 1.7Max.
Distance6360 ly
(1950 pc)
Other designations
RX J2111.6+4809, Nova Cyg 1975, AAVSO 2108+47

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.[1]

V1500 Cygni was discovered on August 29 1975, and reached magnitude 1.7 on the next day. It remained visible to the naked eye for about a week, and 680 days after maximum the star had dimmed by 12.5 magnitudes.

It is an AM Herculis type star, consisting of a red dwarf secondary depositing a stream of material onto a highly magnetized white dwarf primary. The distance of the V1500 Cygni was calculated in 1977 by the McDonald Observatory at 1.95 kiloparsecs (6,360 light years).[2] Additionally, V1500 Cyg was the first asynchronous polar to be discovered. This distinction refers to the fact that the white dwarf's spin period is slightly different from the binary orbital period.[3]

AAVSO light curve showing the magnitude of Nova Cygni 1975. The dates given are Julian day numbers.

See also[edit]


  1. ^ "V1500 Cyg (Nova Cygni 1975)", American Association of Variable Star Observers
  2. ^ Ferland, G. J. (1977). "The interstellar reddening and distance of Nova Cygni 1975 /V1500 Cygni/". Astrophysical Journal. 215: 873. Bibcode:1977ApJ...215..873F. doi:10.1086/155424.
  3. ^ Stockman, H. S.; Schmidt, Gary D.; Lamb, D. Q. (1988). "V1500 Cygni - Discovery of a magnetic nova". The Astrophysical Journal. 332: 282. Bibcode:1988ApJ...332..282S. doi:10.1086/166652.

Further reading[edit]

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