Gamma Delphini
From Wikipedia, the free encyclopedia
| Observation data Equinox J2000 |
|
|---|---|
| Constellation | Delphinus |
| Right ascension | 20h 46m 38.7s/39.5s |
| Declination | +16° 7′ 38″/27″ |
| Apparent magnitude (V) | 5.14/4.27 |
| Characteristics | |
| Spectral type | F7 V/K1 IV |
| U-B color index | 0.08/0.97 |
| B-V color index | 0.49/1.04 |
| Variable type | None/None |
| Astrometry | |
| Radial velocity (Rv) | −7 km/s |
| Proper motion (μ) | RA: −25.88 mas/yr Dec.: −196.27 mas/yr |
| Parallax (π) | 32.14 ± 1.19 mas |
| Distance | 101 ly (31.1 pc) |
| Absolute magnitude (MV) | 2.68/1.81 |
| Visual binary orbit | |
| Companion | γ1 Del / γ2 Del |
| Period (P) | 3249 a |
| Semimajor axis (a) | 13.813" |
| Eccentricity (e) | 0.88 |
| Inclination (i) | 119.2° |
| Node (Ω) | 124.9° |
| Periastron epoch (T) | 50 |
| Other designations | |
|
12 Del, HR 7947/7948, HD 197963/197964, SAO 106475/106476, BD +15 4255 B/A, HIP 102531/102532, WDS 20467+1607B/A
|
|
Gamma Delphini is a binary star in the constellation of Delphinus. Gamma marks one corner of the asterism Job's Coffin. It is one of the best known double stars in the sky. The system consists of a 4th magnitude orange subgiant and a 5th magnitude yellow-white main sequence star and lies approximately 31 parsecs (101 light-years) away.
[edit] Gamma1 Delphini
Gamma1 Delphini is a main sequence star with an apparent magnitude of 5.14 and an absolute magnitude of about +2.68 which equates to a luminosity of about 7.5 times that of the Sun. The spectral class is F7 V.
[edit] Gamma2 Delphini
Gamma2 Delphini is a subgiant star with an apparent magnitude of 4.27 and absolute magnitude of about +1.81 which equates to a luminosity of about 16.5 times that of the Sun. The spectral class is K1 IV.
