Gamma Cygni
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 22m 13.70184s |
| Declination | +40° 15′ 24.0450″ |
| Apparent magnitude (V) | 2.23 |
| Characteristics | |
| Spectral type | F8 Iab |
| U−B color index | +0.54 |
| B−V color index | +0.67 |
| Variable type | suspected |
| Astrometry | |
| Radial velocity (Rv) | -7.5 km/s |
| Proper motion (μ) | RA: +2.39 mas/yr Dec.: -0.91 mas/yr |
| Parallax (π) | 1.78±0.27 mas |
| Distance | approx. 1,800 ly (approx. 560 pc) |
| Absolute magnitude (MV) | −4.54 |
| Details | |
| Mass | 14.5±1.1 M☉ |
| Radius | 183 R☉ |
| Luminosity (bolometric) | 33,023 L☉ |
| Surface gravity (log g) | 1.02±0.10 cgs |
| Temperature | 5,790±100 K |
| Metallicity [Fe/H] | +0.02 dex |
| Rotational velocity (v sin i) | 15 km/s |
| Age | 12 Myr |
| Other designations | |
| Sadr, Sadir, Sador, 37 Cyg, HR 7796, BD+39°4159, HD 194093, SAO 49528, FK5 765, HIP 100453, WDS J20222+4015A | |
| Database references | |
| SIMBAD | data |
Gamma Cygni is a star in the northern constellation of Cygnus, forming the intersection of an asterism of five stars called the Northern Cross. It is officially named Sadr /ˈsædər/, gamma Cygni is its Bayer designation, which that is Latinized from γ Cygni, and abbreviated Gamma Cyg or γ Cyg. Based upon parallax measurements obtained during the Hipparcos mission, it is approximately 1,800 light-years (560 parsecs) from the Sun.
It forms the primary or 'A' component of a multiple star system designated WDS J20222+4015 (the secondary or 'BCD' component is WDS J20222+4015BCD, a close triplet of stars 41" away from γ Cygni).