HD 85622
Binary star system in the constellation Vela
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HD 85622 is a binary star system in the southern constellation of Vela. It is visible to the naked eye with an apparent visual magnitude of 4.58.[1] The distance to HD 85622, as measured from its annual parallax shift of 3.6857 mas,[2] is 880 light years. It is moving further from the Earth with a heliocentric radial velocity of +8 km/s.[8]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Vela[1] |
| Right ascension | 09h 51m 40.66831s[2] |
| Declination | −46° 32′ 51.4401″[2] |
| Apparent magnitude (V) | 4.58[1] |
| Characteristics | |
| Evolutionary stage | Supergiant[3] |
| Spectral type | G5 Ib[3] or G6 IIa[4] |
| B−V color index | 1.20[5] |
| Astrometry | |
| Radial velocity (Rv) | 15.94±2.50[2] km/s |
| Proper motion (μ) | RA: −25.119 mas/yr[2] Dec.: +10.305 mas/yr[2] |
| Parallax (π) | 3.6857±0.1289 mas[2] |
| Distance | 880 ± 30 ly (271 ± 9 pc) |
| Absolute magnitude (MV) | −2.96[1] |
| Orbit[3] | |
| Period (P) | 329.266±0.085 d |
| Eccentricity (e) | 0 (adopted) |
| Periastron epoch (T) | 2453860.281±0.074 HJD |
| Semi-amplitude (K1) (primary) | 13.021±0.012 km/s |
| Details | |
| Mass | 6.2±0.5[6] M☉ |
| Radius | 62.6+2.5 −2.2[2] R☉ |
| Luminosity | 1,602+109 −93[2] L☉ |
| Surface gravity (log g) | 1.65[2] cgs |
| Temperature | 4,761[2] K |
| Rotational velocity (v sin i) | 19.3±1.0[5] km/s |
| Age | 63.7±15.8[6] Myr |
| Other designations | |
| m Vel, CD−45°5508, HD 85622, HIP 48374, HR 3912, SAO 221553[7] | |
| Database references | |
| SIMBAD | data |
This is a single-lined spectroscopic binary with a circular orbit and a period of 329.3 days. The a sin i value is 0.39 AU, where a is the semimajor axis and i is the orbital inclination to the line of sight.[3] This value provides a lower bound on the actual semimajor axis. The system shows a micro-variability in its brightness,[3] and is a source of X-ray emission with an apparent flux of 42.6×10−17 W/m2.[9]
The visible component is a supergiant star with a stellar classification of G5 Ib[3] or G6 IIa.[4] It is about 64 million years old[6] with a projected rotational velocity of 19 km/s.[5] The star has 6.2 times the mass of the Sun[6] and is radiating 1,600 times the Sun's luminosity from its photosphere at an effective temperature of 4,761 K.[6]