HD 70930
Binary star system in the constellation Vela
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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]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Vela[1] |
| Right ascension | 08h 22m 31.6941s[2] |
| Declination | −48° 29′ 25.363″[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]