HD 74180 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. Estimates of its distance to Earth vary between 3,200 and 8,300 light-years. 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. A 2015 study used the Barbier-Chalonge-Divan (BCD) system to derive a luminosity of and a cooler less luminous F8 Ib spectral type.

Distance and size

Multiple papers give different distances for b Velorum. Bailer-Jones et al. (2021) give a distance of about 2530 pc. The Hipparcos spacecraft give a parallax of 0.67 mas, translating into a distance of 1492.5 pc. Aidelman et al. (2015) give a distance of 990 pc. At the Hipparcos distance, bVelorum has its apparent brightness diminished by 1.11magnitudes due to interstellar extinction. b Velorum has an angular diameter estimated at 1.824 mas. The physical size depends on the star's distance, and could be assuming the distance of Aidelman et al., assuming the Hipparcos distance, or even assuming the Bailer-Jones et al. distance.

In chinese astronomy

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. Consequently, Kappa Velorum itself is known as 天社五 (Tiān Shè wǔ), "the Fifth Star of Celestial Earth God's Temple".