Gamma Cygni
Gamma Cygni (γ Cygni, abbreviated Gamma Cyg, γ Cyg), officially named Sadr /ˈsædər/, is a star in the northern constellation of Cygnus, forming the intersection of an asterism of five stars called the Northern Cross. Based upon parallax measurements obtained during the Hipparcos mission, it is approximately 1,800 light-years (560 parsecs) from the Sun.
| 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 | 12.11±0.71 M☉ |
| Radius | 150±80 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 | |
| Database references | |
| SIMBAD | data |
It forms the primary or 'A' component of a multiple star system designated WDS J20222+4015 (the secondary or 'BC' component is CCDM J20222+4015BC, a close pair of stars 40" away from γ Cygni).
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.