Astronomy:HD 74180

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Short description: Supergiant star in the constellation Vela
This page is about b Velorum. For B Velorum, see HD 70930.
b Velorum
Location of b Vel (circled)
Observation data
Equinox J2000.0]] (ICRS)
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 F8 Ib,[4] F0Ia+[5] or F0Ia[6]
U−B color index +0.34[3]
B−V color index +0.67[7]
Variable type suspected α Cyg[5]
Astrometry
Radial velocity (Rv)−25.3[8] km/s
Proper motion (μ) RA: −6.124[2] mas/yr
Dec.: +4.473[2] mas/yr
Parallax (π)0.431 ± 0.101[2] mas
Distance3,230 – 8,250 ly
(990[4] – 2,532[9] pc)
Absolute magnitude (MV)−6.50[4]
Details
Mass12.63[4]–21.4±2.3[10] M☉
Radius186[4][lower-alpha 1] R☉
Luminosity33,884[4] L☉
Surface gravity (log g)1.38[4] cgs
Temperature5,750[4] – 7,839[11] K
Metallicity [Fe/H]0.56[11] dex
Rotational velocity (v sin i)21.7±6[7] km/s
Age7.4±0.8[10][lower-alpha 2] Myr
Other designations
b Velorum, HR 3445, HD 74180, CD−46°4438, FK5 1226, HIP 42570, SAO 220265
Database references
SIMBADdata

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. Estimates of its distance to Earth vary between 3,200 and 8,300 light-years.

Properties

A light curve for HD 74180, adapted from van Leeuwen et al. (1998)[5]

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.[4]

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,[6] 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.[4]

Distance and size

Multiple papers give different distances for b Velorum. Bailer-Jones et al. (2021) give a distance of about 2,530+600
−397 pc (8,250 ly).[9] The Hipparcos spacecraft give a parallax of 0.67±0.16 mas, translating into a distance of 1,492.5 pc (4,868 ly).[14] Aidelman et al. (2015) give a distance of 990 pc (3,200 ly).[4] At the Hipparcos distance, b Velorum has its apparent brightness diminished by 1.11 magnitudes due to interstellar extinction.[11]

b Velorum has an angular diameter estimated at 1.824 mas.[15] The physical size depends on the star's distance, and could be 190 R☉ assuming the distance of Aidelman et al., 290 R☉ assuming the Hipparcos distance, or even 500 R☉ assuming the Bailer-Jones et al. distance.[16]

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.[17] Consequently, Kappa Velorum itself is known as 天社五 (Tiān Shè wǔ), "the Fifth Star of Celestial Earth God's Temple".[18]

Notes

  1. ↑ Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
    (5772/5750)4*34,040=185.91 R⊙
  2. ↑ Assuming 21.4 M☉ as the mass

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific 99 (617): 695. doi:10.1086/132034. Bibcode: 1987PASP...99..695R  Constellation record for this object at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 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. ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 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. doi:10.1051/0004-6361/201425085. Bibcode: 2015A&A...577A..45A. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 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. doi:10.1051/aas:1998129. Bibcode: 1998A&AS..128..117V. 
  6. ↑ 6.0 6.1 Humphreys, R. M. (1978). "Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way". Astrophysical Journal 38: 309. doi:10.1086/190559. Bibcode: 1978ApJS...38..309H. 
  7. ↑ 7.0 7.1 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, doi:10.1051/0004-6361/201118724, Bibcode: 2012A&A...542A.116A  b Velorum's database entry at VizieR.
  8. ↑ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode: 1953GCRV..C......0W. 
  9. ↑ 9.0 9.1 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. doi:10.3847/1538-3881/abd806. ISSN 0004-6256. Bibcode: 2021AJ....161..147B.  Data about this star can be seen here.
  10. ↑ 10.0 10.1 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. doi:10.1111/j.1365-2966.2010.17434.x. ISSN 0035-8711. Bibcode: 2011MNRAS.410..190T.  b Velorum's database entry at VizieR.
  11. ↑ 11.0 11.1 11.2 Luck, R. Earle (2014). "Parameters and Abundances in Luminous Stars". The Astronomical Journal 147 (6): 137. doi:10.1088/0004-6256/147/6/137. Bibcode: 2014AJ....147..137L.  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. doi:10.1111/j.1365-2966.2008.13596.x. ISSN 0035-8711. Bibcode: 2008MNRAS.389..869E.  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. doi:10.1051/0004-6361:20078357. ISSN 0004-6361. Bibcode: 2007A&A...474..653V. https://ui.adsabs.harvard.edu/abs/2007A&A...474..653V.  b Velorum's database entry at VizieR.
  15. ↑ Cruzalèbes, P.; Petrov, R. G.; Robbe-Dubois, S.; Varga, J.; Burtscher, L.; Allouche, F.; Berio, P.; Hofmann, K. -H. et al. (2019-12-01). "A catalogue of stellar diameters and fluxes for mid-infrared interferometry". Monthly Notices of the Royal Astronomical Society 490 (3): 3158–3176. doi:10.1093/mnras/stz2803. ISSN 0035-8711. Bibcode: 2019MNRAS.490.3158C. 
  16. ↑ Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 . The radius (R*) is given by:
    2⋅R*=(10−3⋅990⋅1.824) AU0.0046491 AU/R⨀≈388⋅R⨀
    2⋅R*=(10−3⋅1493⋅1.824) AU0.0046491 AU/R⨀≈586⋅R⨀
    2⋅R*=(10−3⋅2530⋅1.824) AU0.0046491 AU/R⨀≈993⋅R⨀
  17. ↑ (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.
  18. ↑ (in Chinese) 香港太空館 – 研究資源 – 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010.



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