HD 74180

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 $21.4$, 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 $5,772 K$. 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".