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HD 74772
Observation data; Epoch J2000 Equinox J2000
Constellation	Vela
Right ascension	08h 44m 23.94539s
Declination	−42° 38′ 57.3933″
Apparent magnitude (V)	4.05
Characteristics
Spectral type	G6 III
B−V color index	0.874±0.002
Astrometry
Radial velocity (Rv)	−2.0±0.3 km/s
Proper motion (μ)	RA: −22.641 mas/yr ; Dec.: +19.137 mas/yr
Parallax (π)	15.7791 ± 0.3148 mas
Distance	207 ± 4 ly ; (63 ± 1 pc)
Absolute magnitude (MV)	−0.18
Details
Mass	3.2 M☉
Radius	12 R☉
Luminosity	128.02 L☉
Surface gravity (log g)	2.50 cgs
Temperature	5,210 K
Metallicity [Fe/H]	−0.03 dex
Rotational velocity (v sin i)	5.8 km/s
Other designations
	d Vel, CD−42° 4569, GJ 9276, HD 74772, HIP 42884, HR 3477, SAO 220371, WDS J08444-4239A
Database references
SIMBAD	data

HD 74772 (d Velorum) is a single^[10] star in the southern constellation of Vela. It is positioned near the Vela SNR, which gives it an intense X-ray background.^[11] The star is of apparent visual magnitude 4.05,^[2] and hence is visible to the naked eye. Based upon an annual parallax shift of 15.8 mas,^[1] it is located 207 light years from the Sun. It is moving closer to the Earth with a heliocentric radial velocity of −2 km/s.^[4]

This is an evolved G-type giant star with a stellar classification of G6 III.^[3] The interferometry-measured angular diameter of this star is 1.73±0.12 mas,^[12] which, at its estimated distance, equates to a physical radius of about 12 times the radius of the Sun.^[6] It has 3.2^[5] times the mass of the Sun and is radiating 128^[2] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,210 K.^[7]

References

^ ^a ^b ^c ^d ^e ^f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
^ ^a ^b ^c ^d ^e ^f Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
^ ^a ^b Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
^ ^a ^b de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
^ ^a ^b Gondoin, P. (December 1999), "Evolution of X-ray activity and rotation on G-K giants", Astronomy and Astrophysics, 352: 217–227, Bibcode:1999A&A...352..217G.
^ ^a ^b 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:
${\begin{aligned}2\cdot R_{*}&={\frac {(10^{-3}\cdot 63.4\cdot 1.73)\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 23.6\cdot R_{\bigodot }\end{aligned}}$
^ ^a ^b ^c ^d Jones, K. L.; et al. (June 1992), "Spectroscopic investigation of cool giants and the authenticity of their reported microwave emission", Monthly Notices of the Royal Astronomical Society, 256 (3): 535–544, Bibcode:1992MNRAS.256..535J, doi:10.1093/mnras/256.3.535.
^ de Medeiros, J. R.; Mayor, M. (October 1995), "On the link between rotation and coronal activity in evolved stars", Astronomy and Astrophysics, 302: 745, Bibcode:1995A&A...302..745D.
^ "HD 74772". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-08-07.
^ Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
^ Maggio, A.; et al. (1993), "Soft X-ray Emission and Spectra of Evolved Stars from ROSAT Pointed Observations", in Linsky, Jeffrey L.; Serio, Salvatore (eds.), Physics of Solar and Stellar Coronae: G. S. Vaiana Memorial Symposium, held 22-26 June, 1992, in Palermo, Italy, Astrophysics and Space Science Library, vol. 183, Dordrecht, The Netherlands: Kluwer Academoc Publishers, p. 365, Bibcode:1993ASSL..183..365M, doi:10.1007/978-94-011-1964-1_47, ISBN 978-0-7923-2346-4.
^ Richichi, A.; et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039.