HD 74180

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Supergiant star in the constellation Vela

title: "HD 74180" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["bayer-objects", "henry-draper-catalogue-objects", "vela-(constellation)", "binary-stars", "alpha-cygni-variables", "f-type-supergiants", "durchmusterung-objects", "hipparcos-objects", "bright-star-catalogue-objects", "population-i-stars"] description: "Supergiant star in the constellation Vela" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/HD_74180" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Supergiant star in the constellation Vela ::

| name=b Velorum | image= |image=Vela constellation map.svg |float=center |alt= |label= |position=right |width=280 |mark=Red circle.svg |mark_width=12 |mark_link=b Velorum |x=760|y=431 |caption=Location of b Vel (circled) | epoch=J2000 | ra= | dec= | appmag_v=3.81 | constell=Vela | type=Yellow supergiant or yellow hypergiant | class=F8 Ib, F0Ia+ or F0Ia | r-i = | v-r = | b-v = +0.67 | u-b = +0.34 | variable=suspected α Cyg | radial_v=−25.3 | prop_mo_ra=−6.124 | prop_mo_dec=+4.473 | parallax=0.431 | p_error=0.101 | parallax_footnote= | dist_ly=3,2308,250 | dist_pc=9902,532 | dist_footnote= | absmag_v=−6.50 | mass=12.63– | radius={{efn | Applying the Stefan–Boltzmann law with a nominal solar effective temperature of : :\sqrt{(5772/5750)^4 * 34,040} = 185.91\ R\odot}} | luminosity=33,884 | temperature=5,7507,839 | metal_fe=0.56 | gravity=1.38 | rotational_velocity= | age_myr= | names=b Velorum, HR 3445, HD 74180, CD−46°4438, FK5 1226, HIP 42570, SAO 220265 | Simbad=HD+74180

HD 74180 (b Velorum) 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.

Properties

::figure[src="https://upload.wikimedia.org/wikipedia/commons/1/15/HD74180LightCurve.png" caption="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. 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+, 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 , 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 . 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".

Notes

References

. The radius (R*) is given by: :\begin{align} 2\cdot R_* & = \frac{(10^{-3}\cdot 990\cdot 1.824)\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \ & \approx 388\cdot R_{\bigodot} \end{align} \begin{align} 2\cdot R_* & = \frac{(10^{-3}\cdot 1493\cdot 1.824)\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \ & \approx 586\cdot R_{\bigodot} \end{align} \begin{align} 2\cdot R_* & = \frac{(10^{-3}\cdot 2530\cdot 1.824)\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \ & \approx 993\cdot R_{\bigodot} \end{align}

| last1=Ammler-von Eiff | first1=Matthias | last2=Reiners | first2=Ansgar | title=New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars? | journal=Astronomy & Astrophysics | arxiv=1204.2459 | volume=542 | page=A116 | date=June 2012 | doi=10.1051/0004-6361/201118724 | bibcode=2012A&A...542A.116A | s2cid=53666672 }} b Velorum's database entry at VizieR.

References

  1. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues.
  2. {{cite constellation. HD 74180
  3. (1953). "General catalogue of stellar radial velocities". Washington.
  4. {{Cite Gaia DR3. 5521599549054493696
  5. (1978). "Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way". Astrophysical Journal.
  6. (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.
  7. (2019-12-01). "A catalogue of stellar diameters and fluxes for mid-infrared interferometry". Monthly Notices of the Royal Astronomical Society.
  8. {{in lang. zh ''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.
  9. {{in lang. zh [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ala_alz.htm 香港太空館 – 研究資源 – 亮星中英對照表] {{webarchive. link. (2008-10-25 , Hong Kong Space Museum. Accessed on line November 23, 2010.)
  10. (2014). "Parameters and Abundances in Luminous Stars". The Astronomical Journal.
  11. (2015). "Open clusters. II. Fundamental parameters of B stars in Collinder 223, Hogg 16, NGC 2645, NGC 3114, and NGC 6025". Astronomy & Astrophysics.
  12. (1998). "Hipparcos photometry of 24 variable massive stars (α Cygni variables)". Astronomy and Astrophysics Supplement Series.
  13. (2011-01-01). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society.
  14. van Leeuwen, F.. (2007-11-01). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics.
  15. (2008-09-01). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society.
  16. (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.

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bayer-objectshenry-draper-catalogue-objectsvela-(constellation)binary-starsalpha-cygni-variablesf-type-supergiantsdurchmusterung-objectshipparcos-objectsbright-star-catalogue-objectspopulation-i-stars