Tau Cygni
| |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 21h 14m 47.4916s |
| Declination | +38° 02′ 43.141″ |
| Apparent magnitude (V) | 3.80 / 6.69[4] |
| Characteristics | |
| Spectral type | F2 IV + G0 V |
| 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) |
| Details | |
| τ Cyg A | |
| Mass | 1.65[4] M☉ |
| Radius | 2.48[4] R☉ |
| Surface gravity (log g) | 3.87[4] cgs |
| Temperature | 6,600[4] K |
| Metallicity [Fe/H] | 0.05[4] dex |
| τ Cyg B | |
| Mass | 1.03[4] M☉ |
| Radius | 0.93[4] R☉ |
| Surface gravity (log g) | 4.52[4] cgs |
| Temperature | 5,670[4] K |
| Other designations | |
Tau Cygni (τ Cyg) is a binary star system in the constellation Cygnus, approximately 69 light years away from Earth.[1] This visual binary system has a period of 49.6 years.[4]
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]
References
- 1 2 "Simbad Query Result". Simbad. Retrieved October 18, 2007.
- 1 2 "Simbad Query Result". Simbad. Retrieved October 18, 2007.
- 1 2 "Simbad Query Result". Simbad. Retrieved October 18, 2007.
- 1 2 3 4 5 6 7 8 9 10 11 Fuhrmann, Klaus (February 2008), "Nearby stars of the Galactic disc and halo - IV", Monthly Notices of the Royal Astronomical Society 384 (1): 173–224, Bibcode:2008MNRAS.384..173F, doi:10.1111/j.1365-2966.2007.12671.x
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