Nova Cygni 1975 (center), photographed at 07:00 UT August 30, 1975. Also shown are 59 Cygni (magnitude 4.8), 60 Cygni (magnitude 5.4) and 63 Cygni (magnitude 4.5)
V1500 Cygni or Nova Cygni 1975 was a bright nova occurring in 1975 in the constellationCygnus. It had the second highest intrinsic brightness of any nova of the 20th century, exceeded only by CP Puppis in 1942.[10]
V1500 Cygni was discovered shining at an apparent brightness of magnitude 3.0 by Minoru Honda of Kurashiki, Japan on 29 August 1975.[11] It had brightened to magnitude 1.7 on the next day, and then rapidly faded. It remained visible to the naked eye for about a week, and 680 days after reaching 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).[12] More recently the Gaia space observatory determined a distance of approximately 5,100 light years.[1] 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. [13] However, by 2016, x-ray observations strongly suggested that the white dwarf rotation had returned to normal synchronization with the orbit.[4]
V1500 Cygni has a remnant typical of very fast novae, consisting of some clumps and some spherically symmetric diffuse material.[14]
^ abSamus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
^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.
^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.