Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Vela |
Right ascension | 08h 40m 37.57017s[1] |
Declination | −46° 38′ 55.4770″[1] |
Apparent magnitude (V) | 3.81[2] |
Characteristics | |
Spectral type | F0Ia[3] |
U−B color index | +0.34[2] |
B−V color index | +0.71[2] |
Variable type | suspected α Cyg[4] |
Astrometry | |
Radial velocity (Rv) | −25.3[5] km/s |
Proper motion (μ) | RA: −6.055[1] mas/yr Dec.: 4.66[1] mas/yr |
Parallax (π) | 0.68 ± 0.16 mas[1] |
Distance | 990[6] pc |
Absolute magnitude (MV) | −6.50[6] |
Details | |
Mass | 12.63[6] M☉ |
Radius | 196[6][a] R☉ |
Luminosity | 38,000[6] L☉ |
Surface gravity (log g) | 1.38[6] cgs |
Temperature | 5,750[6] K |
Metallicity [Fe/H] | 0.56[7] dex |
Rotational velocity (v sin i) | 21.7[8] km/s |
Other designations | |
Database references | |
SIMBAD | data |
HD 74180 is a binary star in the constellation Vela. It is approximately 3,200 light years from Earth. The primary component is a yellow-white F-type supergiant with a mean apparent magnitude of +3.81, with a 10th magnitude companion 37.5 arcseconds distant.[9]
b Velorum has been classified as a suspected α Cygni variable star which varies by only 0.06 magnitude. There are possible periods near 53, 80, and 160 days, but the variation is largely irregular.[4] It lies less than a degree from the small open cluster NGC 2645, but is not a member.[6]
Several studies have considered b Velorum to be a highly luminous supergiant or hypergiant with an early F spectral type, for example F2 Ia+,[4] F0 Ia,[10] and F4 I.[11] There were corresponding luminosity estimates of several hundred thousand L☉. A 2015 study used the Barbier-Chalonge-Divan (BCD) system to derive a luminosity of 38,000 L☉ and a cooler less luminous F8 Ib spectral type.[6]
In Chinese, 天社 (Tiān Shè), meaning Celestial Earth God's Temple, refers to an asterism consisting of Kappa Velorum, Gamma2 Velorum, b Velorum and Delta Velorum.[12] Consequently, Kappa Velorum itself is known as 天社五 (Tiān Shè wǔ), "the Fifth Star of Celestial Earth God's Temple".[13]