Hd 74180

b Velorum
	Location of b Vel (circled)
Observation data; Epoch J2000 Equinox J2000
Constellation	Vela
Right ascension	08h 40m 37.57017s
Declination	−46° 38′ 55.4770″
Apparent magnitude (V)	3.81
Characteristics
Evolutionary stage	Yellow supergiant or yellow hypergiant
Spectral type	F8 Ib, F0Ia+ or F0Ia
U−B color index	+0.34
B−V color index	+0.67
Variable type	suspected α Cyg
Astrometry
Radial velocity (Rv)	−25.3 km/s
Proper motion (μ)	RA: −6.124 mas/ yr ; Dec.: 4.473 mas/ yr
Parallax (π)	0.431 ± 0.101 mas
Distance	3,230 – 8,250 ly ; (990 – 2,532 pc)
Absolute magnitude (MV)	−6.50
Details
Mass	12.63–21.4±2.3 M☉
Radius	186 R☉
Luminosity	34,040 L☉
Surface gravity (log g)	1.38 cgs
Temperature	5,750 – 7,839 K
Metallicity [Fe/H]	0.56 dex
Rotational velocity (v sin i)	21.7±6 km/s
Age	7.4±0.8 Myr
Other designations
	b Velorum, HR 3445, HD 74180, CD−46°4438, FK5 1226, HIP 42570, SAO 220265
Database references
SIMBAD	data

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]

Distance and size

Multiple papers give different distances for b Velorum. Bailer-Jones et al. (2021) give a distance of about 2,530 pc (8,300 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).^[1] Aidelman et al. (2015) give a distance of 990 pc (3,200 ly).^[3] 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.^[14] 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.^[15]

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]

Notes

^ Margin of error of ⁺¹⁹⁶⁰
₋₁₂₉₀ for the second value
^ This distance applies is b Velorum has spectral type F8Ib.
^ Margin of error of ⁺⁶⁰⁰
₋₃₉₇ for the second value
^ Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
${\sqrt {(5772/5750)^{4}*34,040}}=185.91\ R\odot$
^ From L = 10^{(0.4*(4.74−(M_bol))}, where L is the luminosity and M_bol the bolometric magnitude
^ Assuming 21.4 M_☉ as the mass

References

^ ^a ^b ^c van Leeuwen, F. (2007-11-01). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474: 653–664. arXiv: 0708.1752. doi: 10.1051/0004-6361:20078357. ISSN 0004-6361. b Velorum's database entry at VizieR.
^ ^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.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k 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.
^ ^a ^b ^c ^d ^e 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.
^ ^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.
^ ^a ^b 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.
^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode: 1953GCRV..C......0W.
^ ^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.
^ ^a ^b ^c 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.
^ ^a ^b 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: 190–200. arXiv: 1007.4883. doi: 10.1111/j.1365-2966.2010.17434.x. ISSN 0035-8711. b Velorum's database entry at VizieR.
^ ^a ^b ^c 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.
^ 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: 869–879. arXiv: 0806.2878. doi: 10.1111/j.1365-2966.2008.13596.x. ISSN 0035-8711. b Velorum's database entry at VizieR.
^ 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.
^ Cruzalèbes, P.; Petrov, R. G.; Robbe-Dubois, S.; Varga, J.; Burtscher, L.; Allouche, F.; Berio, P.; Hofmann, K. -H.; Hron, J.; Jaffe, W.; Lagarde, S.; Lopez, B.; Matter, A.; Meilland, A.; Meisenheimer, K. (2019-12-01). "A catalogue of stellar diameters and fluxes for mid-infrared interferometry". Monthly Notices of the Royal Astronomical Society. 490: 3158–3176. arXiv: 1910.00542. doi: 10.1093/mnras/stz2803. ISSN 0035-8711.
^ Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R_*) is given by:
${\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 990\cdot 1.824)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 388\cdot R_{\bigodot }\end{aligned}}$
${\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 1493\cdot 1.824)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 586\cdot R_{\bigodot }\end{aligned}}$
${\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 2530\cdot 1.824)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 993\cdot R_{\bigodot }\end{aligned}}$
^ (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.
^ (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.

[10] Margin of error of ⁺¹⁹⁶⁰
₋₁₂₉₀ for the second value

[11] This distance applies is b Velorum has spectral type F8Ib.

[12] Margin of error of ⁺⁶⁰⁰
₋₃₉₇ for the second value

[14] Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
${\sqrt {(5772/5750)^{4}*34,040}}=185.91\ R\odot$

[Lbol-15] From L = 10^{(0.4*(4.74−(M_bol))}, where L is the luminosity and M_bol the bolometric magnitude

[17] Assuming 21.4 M_☉ as the mass

[HIP-1] van Leeuwen, F. (2007-11-01). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474: 653–664. arXiv: 0708.1752. doi: 10.1051/0004-6361:20078357. ISSN 0004-6361. b Velorum's database entry at VizieR.

[ducati-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.

[aidelman-3] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k 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.

[variable-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. Bibcode: 1998A&AS..128..117V. doi: 10.1051/aas:1998129.

[humphreys-5] 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.

[a-v_e-6] 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.

[DR3-8] 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.

[b-j-9] 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.

[runaway-13] 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: 190–200. arXiv: 1007.4883. doi: 10.1111/j.1365-2966.2010.17434.x. ISSN 0035-8711. b Velorum's database entry at VizieR.

[luck-16] 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.

[eggleton-18] 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: 869–879. arXiv: 0806.2878. doi: 10.1111/j.1365-2966.2008.13596.x. ISSN 0035-8711. b Velorum's database entry at VizieR.

[19] 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.

[crualzalebes-20] Cruzalèbes, P.; Petrov, R. G.; Robbe-Dubois, S.; Varga, J.; Burtscher, L.; Allouche, F.; Berio, P.; Hofmann, K. -H.; Hron, J.; Jaffe, W.; Lagarde, S.; Lopez, B.; Matter, A.; Meilland, A.; Meisenheimer, K. (2019-12-01). "A catalogue of stellar diameters and fluxes for mid-infrared interferometry". Monthly Notices of the Royal Astronomical Society. 490: 3158–3176. arXiv: 1910.00542. doi: 10.1093/mnras/stz2803. ISSN 0035-8711.

[lang2006-21] Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R_*) is given by:
${\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 990\cdot 1.824)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 388\cdot R_{\bigodot }\end{aligned}}$
${\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 1493\cdot 1.824)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 586\cdot R_{\bigodot }\end{aligned}}$
${\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 2530\cdot 1.824)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 993\cdot R_{\bigodot }\end{aligned}}$

[22] (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.

[23] (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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Observation data Epoch J2000 Equinox J2000
Location of b Vel (circled)
Constellation	Vela
Right ascension	08^h 40^m 37.57017^s^[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 (R_v)	−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]
Distance	3,230 – 8,250^[a] ly (990^[3]^[b] – 2,532^[9]^[c] pc)
Absolute magnitude (M_V)	−6.50^[3]

Details

Mass	12.63^[3]–21.4±2.3^[10] `M`_☉
Radius	186^[3]^[d] `R`_☉
Luminosity	34,040^[3]^[e] `L`_☉
Surface gravity (log g)	1.38^[3] cgs
Temperature	5,750^[3] – 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]^[f] Myr

Other designations
b Velorum, HR 3445, HD 74180, CD−46°4438, FK5 1226, HIP 42570, SAO 220265
Database references
SIMBAD	data