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Binary star in the constellation Antlia From Wikipedia, the free encyclopedia
HD 88218 (HR 3992) is a binary star in the southern constellation Antlia. The system has a combined apparent magnitude of 6.14,[2] making it faintly visible to the naked eye. HD 88218 is relatively close at a distance of 103 light years[1] but is receding with a heliocentric radial velocity of 36.7 km/s.[5]
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Antlia |
Right ascension | 10h 09m 31.7681s[1] |
Declination | −35° 51′ 24.4042″[1] |
Apparent magnitude (V) | 6.14[2] |
Characteristics | |
Spectral type | G0 V[3] |
U−B color index | +0.16[4] |
B−V color index | +0.6[4] |
Astrometry | |
Radial velocity (Rv) | 36.7±0.1[5] km/s |
Proper motion (μ) | RA: −445.632 mas/yr[1] Dec.: +18.774 mas/yr[1] |
Parallax (π) | 31.5137 ± 0.0307 mas[1] |
Distance | 103.5 ± 0.1 ly (31.73 ± 0.03 pc) |
Absolute magnitude (MV) | +3.64[2] |
Details | |
A | |
Mass | 1.07±0.03[6] M☉ |
Radius | 1.66[7] R☉ |
Luminosity | 2.88[7] L☉ |
Surface gravity (log g) | 4.03±0.03[8] cgs |
Temperature | 5,878±14[8] K |
Metallicity [Fe/H] | −0.14±0.01[8] dex |
Rotational velocity (v sin i) | 3[9] km/s |
Age | 6.8+0.49 −0.41[10] Gyr |
B | |
Mass | 0.69[11] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
The visible component has a stellar classification of G0 V, indicating the object's status as a solar analogue. As for the companion, it is probably a K-type star based on a mass of 0.69 M☉.[11] As of 2018, both stars have a projected separation of 700 mas along a position angle of 0°.[14] The system has an orbital period of 86.6 years.[11]
Despite the class described above, the primary is starting to evolve off the main sequence at the age of 6.8 billion years, having a low surface gravity[8] and a slightly enlarged radius of 1.66 R☉,[7] with the addition of being chromospherically inactive.[3] Nevertheless, it has 107% the mass of the Sun[6] and radiates at 2.88 times the luminosity of the Sun[7] from its photosphere at an effective temperature of 5,870 K,[8] giving a yellow glow. HD 88218 A has an iron abundance 72% that of the Sun[8] and spins leisurely with a projected rotational velocity of 3 km/s.[9]