Tags: Star.
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 6000 to 7500 kelvins and is larger hotter and several times as bright as our Sun. Its companion 6th magnitude GJ 822.1 B is a yellow main sequence star of the spectral type G0V.
