HD 85622

This article is about m Velorum. For M Velorum, see HD 83446.

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.^[2] The distance to HD 85622 can be estimated from its annual parallax shift of 4.3 mas,^[1] yielding a value of 750 light years. It is moving further from the Earth with a heliocentric radial velocity of +8 km/s.^[6]

HD 85622

Observation data Epoch J2000      Equinox J2000
Constellation	Vela
Right ascension	09h 51m 40.66782s[1]
Declination	−46° 32′ 51.4329″[1]
Apparent magnitude (V)	4.58[2]
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)	+7.8±3.2[6] km/s
Proper motion (μ)	RA: −24.784[1] mas/yr Dec.: +9.843[1] mas/yr
Parallax (π)	4.3323±0.1445 mas[1]
Distance	750 ± 30 ly (231 ± 8 pc)
Absolute magnitude (MV)	−2.96[2]
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[7] M☉
Luminosity	1908.45[8] L☉
Temperature	4,796[8] K
Rotational velocity (v sin i)	19.3±1.0[5] km/s
Age	63.7±15.8[7] Myr
Other designations
m Vel, CD−45° 5508, HD 85622, HIP 48374, HR 3912, SAO 221553[9]
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.^[10]

The visible component is a supergiant star with a stellar classification of G5 Ib^[3] or G6 IIa.^[4] It is about 64^[7] million years old with a projected rotational velocity of 19 km/s.^[5] The star has 6.2^[7] times the mass of the Sun and is radiating 1,908^[8] times the Sun's luminosity from its photosphere at an effective temperature of 4,796 K.^[8]