G Doradus

G Doradus
Location of G Doradus on the map (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Dorado
Right ascension 05h 32m 59.56572s[1]
Declination −64° 13′ 39.0537″[1]
Apparent magnitude (V) 5.34±0.01[2]
Characteristics
Spectral type G8/K0 III[3]
U−B color index +0.85[4]
B−V color index +1.04[4]
Astrometry
Radial velocity (Rv)9.8±2.8[5] km/s
Proper motion (μ) RA: +45.741 mas/yr[1]
Dec.: −3.051 mas/yr[1]
Parallax (π)13.9330 ± 0.2335 mas[1]
Distance234 ± 4 ly
(72 ± 1 pc)
Absolute magnitude (MV)+1.08[6]
Orbit[7]
Period (P)180.8757 d
Semi-major axis (a)0.320 AU
Eccentricity (e)0.509±0.010
Inclination (i)52.2±5.2[8]°
Longitude of the node (Ω)45.4±6.6[8]°
Periastron epoch (T)2,423,108.42±0.65 JD
Argument of periastron (ω)
(secondary)		332.93±1.61°
Semi-amplitude (K1)
(primary)		22.36±0.35 km/s
Details
A
Mass3.47[9] M☉
Radius10.5+0.1
−0.2[1] R☉
Luminosity48.4+1.6
−1.5[1] L☉
Surface gravity (log g)2.61[10] cgs
Temperature4819±123[11] K
Metallicity [Fe/H]−0.20[12] dex
Rotational velocity (v sin i)<1.0[13] km/s
Age556+153
−188[1] Myr
B
Mass1.87[9] M☉
Other designations
G Dor, 28 G. Doradus[14], CPD−64°456, FK5 2418, GC 6927, HD 37297, HIP 26001, HR 1917, SAO 249309, TIC 149304313[15]
Database references
SIMBADdata

G Doradus (HD 37297; HR 1917; 28 G. Doradus) is a spectroscopic binary located in the southern constellation Dorado, the dolphinfish. It has an apparent magnitude of 5.34,[2] making it faintly visible to the naked eye under ideal conditions. The system is located relatively close at a distance of 234 light-years based on Gaia DR3 parallax measurements but it is receding with a heliocentric radial velocity of approximately 9.8 km/s.[5] At its current distance, G Doradus' brightness is diminished by a quarter of a magnitude due to interstellar extinction[16] and it has an absolute magnitude of +1.08.[6] The bayer designation "G Doradus" was not assigned by Benjamin Gould or Lacaille. It merely arose due to the designation assigned by Gould; 28 G. Doradus.[17]

The visible component has a stellar classification of G8/K0 III,[3] indicating that it is an evolved star with the characteristics of a G8 and K0 giant star. It has 3.47 times the mass of the Sun[9] but at the age of 556 million years, it has expanded to 10.5 times the radius of the Sun.[1] It radiates 48.4 times the luminosity of the Sun[1] from its enlarged photosphere at an effective temperature of 4,819 K,[11] giving it an orangish-yellow hue when viewed in the night sky. G Doradus is slightly metal deficient with an iron abundance of [Fe/H] = −0.20[12] and it spins too slowly for its projected rotational velocity to be measured accurately.[13]

G Doradus is a single-lined spectroscopic binary; the components – which have a separation of 0.32 AU – take 181 days to circle each other in an elliptical orbit, but the orbit is not well constrained.[7] Although only the primary can be observed in the spectrum, the masses of both components can be determined. Krachieva et al. (1980) derives a mass of 1.87 M☉ for the companion,[9] which might be an A-type star.

  1. ^ a b c d e f g h i Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Houk1975 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Lunt1924 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Jancart2005 was invoked but never defined (see the help page).
  9. ^ a b c d Cite error: The named reference Kraicheva1980 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Anders2019 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference Eggen1989 was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference De Medeiros2014 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Gontcharov2017 was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference wagman was invoked but never defined (see the help page).