Gamma Delphini
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Delphinus |
| γ1 | |
| Right ascension | 20h 46m 38.86045s |
| Declination | +16° 07′ 26.8516″ |
| Apparent magnitude (V) | 5.14 |
| γ2 | |
| Right ascension | 20h 46m 39.49919s |
| Declination | +16° 07′ 27.4358″ |
| Apparent magnitude (V) | 4.360 |
| Characteristics | |
| γ1 | |
| Spectral type | F7V |
| U−B color index | 0.08 |
| B−V color index | 0.49 |
| γ2 | |
| Evolutionary stage | Subgiant |
| Spectral type | K1IV |
| U−B color index | 0.97 |
| B−V color index | 1.04 |
| Astrometry | |
| γ1 | |
| Radial velocity (Rv) | −7.25±0.44 km/s |
| Proper motion (μ) | RA: −11.153 mas/yr Dec.: −203.341 mas/yr |
| Parallax (π) | 28.4068±0.1504 mas |
| Distance | 114.8 ± 0.6 ly (35.2 ± 0.2 pc) |
| Absolute magnitude (MV) | 2.24 |
| γ2 | |
| Radial velocity (Rv) | −6.33±0.35 km/s |
| Proper motion (μ) | RA: −29.851 mas/yr Dec.: −196.058 mas/yr |
| Parallax (π) | 28.5183 ± 0.4772 mas |
| Distance | 114 ± 2 ly (35.1 ± 0.6 pc) |
| Absolute magnitude (MV) | 1.81 |
| Orbit | |
| Companion | γ1 |
| Period (P) | 3,249 yr |
| Semi-major axis (a) | 10.22″ |
| Eccentricity (e) | 0.88 |
| Inclination (i) | 148.78° |
| Longitude of the node (Ω) | 88.06° |
| Periastron epoch (T) | 2,305 |
| Argument of periastron (ω) (secondary) | 331.16° |
| Details | |
| γ1 | |
| Mass | 1.61±0.04 M☉ |
| Radius | 2.60±0.12 R☉ |
| Luminosity | 10.2 L☉ |
| Surface gravity (log g) | 3.79±0.05 cgs |
| Temperature | 6,295±25 K |
| Metallicity [Fe/H] | 0.06±0.02 dex |
| Rotational velocity (v sin i) | 7.8 km/s |
| Age | 1.85±0.17 Gyr |
| γ2 | |
| Mass | 1.99±0.06 M☉ |
| Radius | 8.43±0.33 R☉ |
| Luminosity | 33.1 L☉ |
| Surface gravity (log g) | 3.04±0.06 cgs |
| Temperature | 4,798±20 K |
| Metallicity [Fe/H] | 0.12±0.03 dex |
| Rotational velocity (v sin i) | 3.6 km/s |
| Age | 1.81±0.11 Gyr |
| Other designations | |
| γ Del, 12 Delphini, BD+15°4255, CCDM J20467+1607, WDS 20467+1607 | |
| γ1: HD 197963, HIP 102531, HR 7947, SAO 106475 | |
| γ2: HD 197964, HIP 102532, HR 7947/7948, SAO 106476 | |
| Database references | |
| SIMBAD | γ Del |
| γ1 Del | |
| γ2 Del | |
Gamma Delphini, which is Latinized from γ Delphini, is a wide binary star system in the northern constellation of Delphinus. The star marks one corner of the asterism "Job's Coffin". The pair can be split with a modest amateur telescope and have been described as "one of the prettier pairs in the sky", with their contrasting colors said to be orange and lime in appearance. Together, the system is visible to the naked eye with a combined apparent visual magnitude of 3.87.