G Doradus
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  | |
| 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] |
| Distance | 234 ± 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 | |
| Mass | 3.47[9] M☉ |
| Radius | 10.5+0.1 −0.2[1] R☉ |
| Luminosity | 48.4+1.6 −1.5[1] L☉ |
| Surface gravity (log g) | 2.61[10] cgs |
| Temperature | 4819±123[11] K |
| Metallicity [Fe/H] | −0.20[12] dex |
| Rotational velocity (v sin i) | <1.0[13] km/s |
| Age | 556+153 −188[1] Myr |
| B | |
| Mass | 1.87[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 | |
| SIMBAD | data |
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 designation "G Doradus" is not a Bayer designation assigned by Benjamin Gould or Lacaille; it arose from the Gould designation 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.
