Q Cygni

Q Cygni
Location of Q Cygni (circled in red)
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension 21h 41m 43.928s[1]
Declination 42° 50′ 29.04″[1]
Apparent magnitude (V) 3.0 - 15.6[2]
Characteristics
Spectral type K5[3]
Variable type Nova[2]
Astrometry
Parallax (π)0.729 ± 0.024 mas[4]
Distance1372+51
−42[4] (741[5] - 3,300[6]) pc
Absolute magnitude (MV)−9.1 - +2.9[4]
Details
White dwarf
Mass0.8[5] M☉
Surface gravity (log g)8.5[5] cgs
Temperature31,000[5] K
secondary
Mass0.6[3] M☉
Other designations
Nova Cygni 1876, HR 8296, BD+42°4182a, AAVSO 2137+42, 2MASS J21414393+4250290, Gaia DR2 1966874711229398656
Database references
SIMBADdata

Q Cygni (Q Cyg), 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.

One of the earliest novae recorded,[6] Q Cygni was discovered by astronomer Johann Friedrich Julius Schmidt on November 24, 1876.[7] The star had undergone a nova, brightening to about 3rd magnitude and remaining as bright for four days.[6]

The system is termed a cataclysmic variable,[3] composed of a white dwarf in close orbit with another star that orbit each other every 10 hours. The white dwarf is surrounded by an accretion disc, which blazes much brighter than the star it circles. The system has been estimated to be 740 ± 11 parsecs distant.[5] The secondary star has been estimated to be around 0.6 times as massive as the Sun, making it an orange dwarf of spectral type K5.[3] Also known as a donor star, the secondary supplies mass to the white dwarf via its accretion disc.[3]

A small nebulous disc was reported around the nova and this led to it being listed in the New General Catalogue as a possible planetary nebula. No nebulosity is visible in modern observations and the Revised New General Catalogue lists this as a "non-existent" object.[8]

The light curve of Q Cygni. The red points are from a table published by Schmidt, and the blue points were measured from a plot published by Lockyer.[9][10]
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