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.^[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]

HD 85622

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]