HD 74180 (b Velorum) is a single star in the constellation Vela. It is a yellow-white F-type supergiant with a mean apparent magnitude of +3.81 and a spectral classification F8Ib.
Properties
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. It lies less than a degree from the small open cluster NGC 2645, but is not a member.
Several studies have considered b Velorum to be a highly luminous supergiant or hypergiant with an early F spectral type, for example F2 Ia+, F0 Ia, and F4 I. There were corresponding luminosity estimates of . Aidelman et al. (2015) used the Barbier-Chalonge-Divan (BCD) system to derive a luminosity of and a cooler less luminous F8 Ib spectral type. Kasikov et al. (2026) arrived with a luminosity of based on an stellar radius of and an effective temperature of 7,540 K from the average of earlier spectroscopic measurements.
Parallax measurements by the Hipparcos and Gaia spacecraft imply distances of () and (), respectively. Aidelman et al. (2015) give a distance of . Kasikov et al. (2026) estimated the distance using stars with similar proper motion and reliable Gaia parallaxes, giving a value of . This is consistent with the distance to NGC 2645, despite the star being not a member.
In Chinese astronomy In Chinese, (), meaning Celestial Earth God's Temple, refers to an asterism consisting of Kappa Velorum, Gamma2 Velorum, b Velorum and Delta Velorum. 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, . Consequently, Kappa Velorum itself is known as (), "the Fifth Star of Celestial Earth God's Temple". 香港太空館 – 研究資源 – 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010.
References b Velorum's database entry at VizieR.
b Velorum's database entry at VizieR.
b Velorum's database entry at VizieR.
b Velorum's database entry at VizieR.
b Velorum's database entry at VizieR.
Data about this star can be seen here.