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]
A light curve for HD 74180, adapted from van Leeuwen et al. (1998)[4]
Binary star system in the constellation Vela
This article is about b Velorum. For B Velorum, see HD 70930.
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 clusterNGC 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 thousandL☉. A 2015 study used the Barbier-Chalonge-Divan (BCD) system to derive a luminosity of 38,000L☉ and a cooler less luminous F8 Ib spectral type.[6]
Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
Houk, Nancy (1978). "Michigan catalogue of two-dimensional spectral types for the HD stars". Ann Arbor: Dept. Of Astronomy, University of Michigan. 2. Bibcode:1978MSS...C02....0H.
Ammler-von Eiff, Matthias; Reiners, Ansgar (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: A116, arXiv:1204.2459, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724, S2CID53666672
Humphreys, R. M. (1978). "Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way". Astrophysical Journal. 38: 309. Bibcode:1978ApJS...38..309H. doi:10.1086/190559.
Mersch, G.; Heck, A. (1980). "Prediction of spectral classification from photometric observations - Application of the UVBY beta photometry and the MK spectra classification. II - General case". Astronomy and Astrophysics. 85: 93. Bibcode:1980A&A....85...93M.
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