HD 70930

This article is about B Velorum. For b Velorum, see HD 74180.

HD 70930 is a binary star^[9] system in the southern constellation of Vela. It has the Bayer designation B Velorum, while HD 70930 is the star's identifier in the Henry Draper catalogue. With a combined apparent visual magnitude of 4.79,^[1] it is visible to the naked eye as a faint point of light. The distance to this system is approximately 1,700 light years based on parallax,^[2] and it has an absolute magnitude of −3.74.^[1] It is drifting further away from the Sun with a radial velocity of about +27 km/s.^[1] The system is a member of the Vel OB2 association of co-moving stars.^[10]

HD 70930

Observation data Epoch J2000      Equinox J2000
Constellation	Vela[1]
Right ascension	08h 22m 31.6941s[2]
Declination	−48° 29′ 25.3631″[2]
Apparent magnitude (V)	4.79[1] (5.14 + 6.08)[3]
Characteristics
Spectral type	B1V[4] or B2III[5]
B−V color index	−0.146±0.002[1]
Astrometry
Radial velocity (Rv)	+27.0±4.5[1] km/s
Proper motion (μ)	RA: −5.10±0.39[2] mas/yr Dec.: +7.76±0.33[2] mas/yr
Parallax (π)	1.90±0.32 mas[2]
Distance	approx. 1,700 ly (approx. 530 pc)
Absolute magnitude (MV)	−3.74[1]
Details
Mass	15.6±0.8[4] M☉
Radius	13.6[6] R☉
Luminosity	20,893[7] L☉
Surface gravity (log g)	2.74[6] cgs
Temperature	23,532[7] K
Rotational velocity (v sin i)	220[7] km/s
Age	10.0±0.1[4] Myr
Other designations
I 67[3], B Velorum, CD−48°3734, HD 70930, HIP 41039, HR 3294, SAO 219848, CCDM 08225-4829, WDS J08225-4829AB[8]
Database references
SIMBAD	data

The double nature of this system was discovered in 1896 by Scottish astronomer Robert T. A. Innes^[3] – it is now known to be a double-lined spectroscopic binary.^[11] The magnitude 5.14^[3] primary component has a blue-white hue and has been assigned stellar classifications of B1V^[4] and B2III,^[5] matching a B-type main-sequence star or a giant star, respectively. It is a massive object – over 15 times the mass of the Sun – and is around 10 million years old.^[4] The star has a high rate of spin, showing a projected rotational velocity of 220 km/s.^[7] Its companion, at magnitude +6.08, is located at an angular separation of 0.8″ along a position angle of 139°, as of 2008.^[3]