Apparent magnitude (V) 1.7Max. 18Min Distance 6,360 ly | Constellation Cygnus | |
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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.
V1500 Cygni was discovered on August 29 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). 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 than the binary orbital period.