Tau Cygni

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GJ 822.1 A / GJ 822.1 B [1][2][3]
Observation data
Epoch J2000.0
Constellation
(pronunciation)		 Cygnus
Right ascension 21h 14m 47.4916s
Declination +38° 2' 43.141"
Apparent magnitude (V) 3.84 / 6.44
Characteristics
Spectral type F2IV / G0V
U-B color index +0.03 / +0.09
B-V color index +0.38 / +0.60
Astrometry
Radial velocity (Rv) -21.1 km/s
Proper motion (μ) RA: 195.75 mas/yr
Dec.: 410.03 mas/yr
Parallax (π) 47.80 ± 0.61 mas
Distance 68.2 ± 0.9 ly
(20.9 ± 0.3 pc)
Other designations
Tau Cygni, 65 Cygni, HR 8130, BD+37°4240, HD 202444, SAO 71121, HIP 104887, GC 29723, CCDM J21148+3803AB

Tau Cygni (τ Cyg) is a binary star system in the constellation Cygnus, approximately 69 light years away from Earth.[1] 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 our Sun.[2] Its companion, 6th magnitude GJ 822.1 B, is a yellow main sequence star of the spectral type G0V. It is similar to our Sun in size, surface temperature, and luminosity.[3]

[edit] References

  1. ^ a b Simbad Query Result. Simbad. Retrieved on October 18, 2007.
  2. ^ a b Simbad Query Result. Simbad. Retrieved on October 18, 2007.
  3. ^ a b Simbad Query Result. Simbad. Retrieved on October 18, 2007.
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