HD 74180

Last updated
b Velorum
Vela constellation map.svg
Red circle.svg
Location of b Vel (circled)
Observation data
Epoch J2000       Equinox J2000
Constellation Vela [1]
Right ascension 08h 40m 37.57121s [2]
Declination −46° 38′ 55.4644″ [2]
Apparent magnitude  (V)3.81 [3]
Characteristics
Evolutionary stage Yellow supergiant or yellow hypergiant
Spectral type F0Ia [4] or F0Ia+ [5]
U−B color index +0.34 [3]
B−V color index +0.67 [6]
Variable type suspected α Cyg [5]
Astrometry
Radial velocity (Rv)−25.3 [7] km/s
Proper motion (μ)RA: −6.124 [2] mas/yr
Dec.: +4.473 [2] mas/yr
Parallax (π)0.431±0.101  mas [2]
Distance 5,400+110
−140  ly
(1,657+33
−44  pc) [8]
Absolute magnitude  (MV)−6.50 [9]
Details
Mass 21.4±2.3 [10]   M☉
Radius 325±28 [8]   R☉
Luminosity 316,000+73,000
−65,000 [8]   L☉
Surface gravity (log g)1.38 [9]   cgs
Temperature 7,839 [11]   K
Metallicity [Fe/H]+0.56 [11]   dex
Rotational velocity (v sin i)21.7±6 [6]  km/s
Age 7.4±0.8 [10]   Myr
Other designations
b  Velorum, HR  3445, HD  74180, CD−46°4438, FK5 1226, HIP  42570, SAO  220265
Database references
SIMBAD data

HD 74180 (b Velorum) 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.

Contents

Properties

A light curve for HD 74180, adapted from van Leeuwen et al. (1998) HD74180LightCurve.png
A light curve for HD 74180, adapted from van Leeuwen et al. (1998)

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. [5] It lies less than a degree from the small open cluster NGC 2645, but is not a member. [9]

Several studies have considered b Velorum to be a highly luminous supergiant or hypergiant with an early F spectral type, for example F2 Ia+, [5] F0 Ia, [4] and F4 I. [13] There were corresponding luminosity estimates of several hundred thousand  L☉. Aidelman et al. (2015) used the Barbier-Chalonge-Divan (BCD) system to derive a luminosity of 34,000 L☉ and a cooler less luminous F8 Ib spectral type. [9] Kasikov et al. (2026) arrived with a luminosity of 316,000 L☉ based on an stellar radius of 325±28  R☉ and an effective temperature of 7,540  K from the average of earlier spectroscopic measurements. [8]

Parallax measurements by the Hipparcos and Gaia spacecrafts imply distances of 1490±360  pc (4,860  ly) [14] and 2,530+600
−397 pc (8,250 ly), respectively. [15] Aidelman et al. (2015) give a distance of 990 pc (3,200 ly). [9] Kasikov et al. (2026) estimated the distance using stars with similar proper motion and reliable Gaia parallaxes, giving a value of 1,657 parsecs (5,400 ly). This is consistent with the distance to NGC 2645, despite the star being not a member. [8]

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. [16] Consequently, Kappa Velorum itself is known as 天社五 (Tiān Shè wǔ), "the Fifth Star of Celestial Earth God's Temple". [17]

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific . 99 (617): 695. Bibcode:1987PASP...99..695R. doi: 10.1086/132034 . Constellation record for this object at VizieR.
  2. 1 2 3 4 5 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.
  3. 1 2 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.
  4. 1 2 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.
  5. 1 2 3 4 5 Van Leeuwen, F.; Van Genderen, A. M.; Zegelaar, I. (1998). "Hipparcos photometry of 24 variable massive stars (α Cygni variables)". Astronomy and Astrophysics Supplement Series. 128: 117–129. Bibcode:1998A&AS..128..117V. doi: 10.1051/aas:1998129 .
  6. 1 2 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, S2CID   53666672 b Velorum's database entry at VizieR.
  7. ↑ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W.
  8. 1 2 3 4 5 Kasikov, A.; Mehner, A.; Kolka, I.; Aret, A. (2026-02-02). "Painting a Family Portrait of the Yellow Super- and Hypergiants in the Milky Way I. Constraining the Distances and Luminosities". Astronomy and Astrophysics. arXiv: 2602.02449 .
  9. 1 2 3 4 5 Aidelman, Y.; Cidale, L. S.; Zorec, J.; Panei, J. A. (2015). "Open clusters. II. Fundamental parameters of B stars in Collinder 223, Hogg 16, NGC 2645, NGC 3114, and NGC 6025". Astronomy & Astrophysics. 577: A45. Bibcode:2015A&A...577A..45A. doi: 10.1051/0004-6361/201425085 . hdl: 11336/14076 .
  10. 1 2 Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (2011-01-01). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv: 1007.4883 . Bibcode:2011MNRAS.410..190T. doi: 10.1111/j.1365-2966.2010.17434.x . ISSN   0035-8711. b Velorum's database entry at VizieR.
  11. 1 2 Luck, R. Earle (2014). "Parameters and Abundances in Luminous Stars". The Astronomical Journal. 147 (6): 137. Bibcode:2014AJ....147..137L. doi: 10.1088/0004-6256/147/6/137 . b Velorum's database entry at VizieR.
  12. ↑ Eggleton, P. P.; Tokovinin, A. A. (2008-09-01). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv: 0806.2878 . Bibcode:2008MNRAS.389..869E. doi: 10.1111/j.1365-2966.2008.13596.x . ISSN   0035-8711. b Velorum's database entry at VizieR.
  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.
  14. ↑ van Leeuwen, F. (2007-11-01). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv: 0708.1752 . Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. ISSN   0004-6361. b Velorum's database entry at VizieR.
  15. ↑ Bailer-Jones, C. A. L.; Rybizki, J.; Fouesneau, M.; Demleitner, M.; Andrae, R. (2021-03-01). "Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3". The Astronomical Journal. 161 (3): 147. arXiv: 2012.05220 . Bibcode:2021AJ....161..147B. doi: 10.3847/1538-3881/abd806 . ISSN   0004-6256. Data about this star can be seen here.
  16. ↑ (in Chinese)中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN   978-986-7332-25-7.
  17. ↑ (in Chinese) 香港太空館 – 研究資源 – 亮星中英對照表 Archived 2008-10-25 at the Wayback Machine , Hong Kong Space Museum. Accessed on line November 23, 2010.
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