Magnitude 3.74 | Period 2.2 years Apparent magnitude (V) 3.74 | |
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Tau Cygni (τ Cyg) is a binary star system in the constellation Cygnus, approximately 69 light years away from Earth. This visual binary system has a period of 49.6 years.
The main star, 4th magnitude GJ 822.1 A, is a yellowish white subgiant star of the spectral type F2IV. It therefore has a surface temperature of 6,000 to 7,500 kelvins and is larger, hotter, and several times as bright as the Sun. Its companion, 6th magnitude GJ 822.1 B, is a yellow main sequence star of the spectral type G0V. It is similar to the Sun in size, surface temperature, and luminosity.
References
Tau Cygni Wikipedia(Text) CC BY-SA