HD 74180

This article is about b Velorum. For B Velorum, see HD 70930.
b Velorum
Location of b Vel (circled)
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
Evolutionary stage Yellow supergiant or yellow hypergiant
Spectral type F8 Ib,[3] F0Ia+[4] or F0Ia[5]
U−B color index +0.34[2]
B−V color index +0.67[6]
Variable type suspected α Cyg[4]
Astrometry
Radial velocity (Rv)−25.3[7] km/s
Proper motion (μ) RA: −6.124[8] mas/yr
Dec.: 4.473[8] mas/yr
Parallax (π)0.431 ± 0.101 mas[9]
Distance3,230 – 8,250[a] ly
(990[3][b] – 2,532[9][c] pc)
Absolute magnitude (MV)−6.50[3]
Details
Mass12.63[3]–21.4±2.3[10] M☉
Radius186[3][d] R☉
Luminosity34,040[3][e] L☉
Surface gravity (log g)1.38[3] cgs
Temperature5,750[3] – 7,839[11] K
Metallicity [Fe/H]0.56[11] dex
Rotational velocity (v sin i)21.7±6[6] km/s
Age7.4±0.8[10][f] Myr
Other designations
b Velorum, HR 3445, HD 74180, CD−46°4438, FK5 1226, HIP 42570, SAO 220265
Database references
SIMBADdata

HD 74180 is a single[12] 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.

A light curve for HD 74180, adapted from van Leeuwen et al. (1998)[4]

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.[3]

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,[5] and F4 I.[13] 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 34,000 L☉ and a cooler less luminous F8 Ib spectral type.[3]

  1. ^ a b Cite error: The named reference HIP was invoked but never defined (see the help page).
  2. ^ a b 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.
  3. ^ a b c d e f g h i j Cite error: The named reference aidelman was invoked but never defined (see the help page).
  4. ^ a b c d e Cite error: The named reference variable was invoked but never defined (see the help page).
  5. ^ a b 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.
  6. ^ a b Cite error: The named reference a-v e was invoked but never defined (see the help page).
  7. ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W.
  8. ^ a b Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  9. ^ a b Cite error: The named reference b-j was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference runaway was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference luck was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference eggleton was invoked but never defined (see the help page).
  13. ^ 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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