Gamma Delphini

γ Delphini
Location of γ Delphini (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Delphinus
γ1
Right ascension 20h 46m 38.86045s[1]
Declination +16° 07′ 26.8516″[1]
Apparent magnitude (V) 5.14
γ2
Right ascension 20+46
−39.49919[2]
Declination +16° 07′ 27.4358″[2]
Apparent magnitude (V) 4.360[3]
Characteristics
γ1
Spectral type F7V[4]
U−B color index 0.08
B−V color index 0.49
γ2
Evolutionary stage Subgiant[5]
Spectral type K1IV[6]
U−B color index 0.97
B−V color index 1.04
Astrometry
γ1
Radial velocity (Rv)−7.25±0.44[7] km/s
Proper motion (μ) RA: −11.153[1] mas/yr
Dec.: −203.341[1] mas/yr
Parallax (π)28.4068 ± 0.1504 mas[1]
Distance114.8 ± 0.6 ly
(35.2 ± 0.2 pc)
Absolute magnitude (MV)2.24[4]
γ2
Radial velocity (Rv)−6.33±0.35[7] km/s
Proper motion (μ) RA: −29.851[2] mas/yr
Dec.: −196.058[2] mas/yr
Parallax (π)28.5183 ± 0.4772 mas[2]
Distance114 ± 2 ly
(35.1 ± 0.6 pc)
Absolute magnitude (MV)1.81[8]
Orbit[9]
Companionγ1
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[7]
γ1
Mass1.61±0.04 M☉
Radius2.60±0.12 R☉
Luminosity10.2 L☉
Surface gravity (log g)3.79±0.05 cgs
Temperature6,295±25 K
Metallicity [Fe/H]0.06±0.02 dex
Rotational velocity (v sin i)7.8[4] km/s
Age1.85±0.17 Gyr
γ2
Mass1.99±0.06 M☉
Radius8.43±0.33 R☉
Luminosity33.1 L☉
Surface gravity (log g)3.04±0.06 cgs
Temperature4,798±20 K
Metallicity [Fe/H]0.12±0.03 dex
Rotational velocity (v sin i)3.6[10] km/s
Age1.81±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
SIMBADγ 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.[11] Together, the system is visible to the naked eye with a combined apparent visual magnitude of 3.87.[12]

  1. ^ a b c d e Cite error: The named reference GaiaDR2_1 was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference GaiaDR2_2 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Mason_et_al_2014 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Luck2017 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Abr2019 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Cenarro_et_al_2007 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference Villaver_et_al_2013 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Hale, A. was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Massarotti_et_al_2008 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Consolmagno_Davis_2011 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Kaler was invoked but never defined (see the help page).