Gamma Delphini

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Gamma1Delphini/Gamma2Delphini

Gamma Delphini
Observation data
Epoch J2000
Constellation
(pronunciation)
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
Distance 101 ly (31.1 pc)
Absolute magnitude (MV) 2.68/1.81
Visual binary orbit
Companion γ1 Del / γ2 Del
Period (P) 3249 yr
Semimajor axis (a) 13.813"
Eccentricity (e) 0.88
Inclination (i) 119.2°
Longitude of the 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.
Database references
SIMBAD data

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.

[edit] Reference

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