Nu Orionis

ν Orionis
	Location of ν Orionis (circled)
Observation data; Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation	Orion
Right ascension	06h 07m 34.32588s
Declination	+14° 46′ 06.5061″
Apparent magnitude (V)	4.42
Characteristics
Spectral type	B3 V or B3 IV
U−B color index	−0.67
B−V color index	−0.18
Astrometry
Radial velocity (Rv)	+24.1 km/s
Proper motion (μ)	RA: +6.78 mas/yr ; Dec.: −20.23 mas/yr
Parallax (π)	6.32 ± 0.33 mas
Distance	520 ± 30 ly ; (158 ± 8 pc)
Orbit
Period (P)	131.211 d
Eccentricity (e)	0.64
Periastron epoch (T)	2436475.852 JD
Argument of periastron (ω); (secondary)	6.6°
Semi-amplitude (K1); (primary)	33.3 km/s
Details
ν Ori A
Mass	6.7±0.1 M☉
Radius	4.3 R☉
Luminosity	1,965 L☉
Surface gravity (log g)	4.06 cgs
Temperature	17,880 K
Metallicity [Fe/H]	−0.05 dex
Rotational velocity (v sin i)	30 km/s
Age	26.3±5.3 Myr
Other designations
	ν Ori, 67 Orionis, BD+14° 1152, FK5 232, HD 41753, HIP 29038, HR 2159, SAO 95259.
Database references
SIMBAD	data

Nu Orionis (ν Orionis) is a binary star^[11] system in the northeastern part of the constellation Orion. It should not be confused with the variable star NU Orionis.^[12] Nu Orionis has an apparent visual magnitude of 4.42,^[2] which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 0.00632 arcseconds,^[1] the distance to this system is roughly 520 light years.

This is a single-lined spectroscopic binary system,^[9] which means that only the absorption line features of one of the components can be distinguished. The components orbit each other with a period of 131.2 days and an eccentricity of 0.64.^[6] Depending on the source, the primary is either a B-type main sequence star with a stellar classification of B3 V,^[3] or a more evolved B-type subgiant star of class B3 IV.^[4] It has an angular diameter of 0.251 mas,^[13] which, at the estimated distance of this system, yields a physical size of about 4.3 times the radius of the Sun.^[7] The mass is 6.7^[4] times that of the Sun and it shines with 1,965^[3] times the solar luminosity from its outer atmosphere at an effective temperature of 17,880 K.^[8]

References

^ ^a ^b ^c ^d ^e ^f van Leeuwen, F. (2007), "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, S2CID 18759600.
^ ^a ^b ^c ^d Crawford, D. L.; et al. (1971), "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere", The Astronomical Journal, 76: 1058, Bibcode:1971AJ.....76.1058C, doi:10.1086/111220.
^ ^a ^b ^c ^d Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349–360, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355, S2CID 111387483.
^ ^a ^b ^c ^d ^e Tetzlaff, N.; et al. (2011), "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, S2CID 118629873.
^ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E.
^ ^a ^b Pourbaix, D.; et al. (2004), "S_B⁹: The ninth catalogue of spectroscopic binary orbits", Astronomy and Astrophysics, 424 (2): 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
^ ^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:
${\begin{aligned}2\cdot R_{*}&={\frac {(158.2\cdot 0.251\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 8.5\cdot R_{\bigodot }\end{aligned}}$
^ ^a ^b ^c ^d Gies, Douglas R.; Lambert, David L. (March 1992), "Carbon, nitrogen, and oxygen abundances in early B-type stars", Astrophysical Journal, Part 1, 387: 673–700, Bibcode:1992ApJ...387..673G, doi:10.1086/171116.
^ ^a ^b Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590.
^ "nu. Ori". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-11-03.
^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "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, S2CID 14878976.
^ Marett-Crosby, Michael (2013), Twenty-Five Astronomical Observations That Changed the World: And How To Make Them Yourself, The Patrick Moore Practical Astronomy Series, Springer Science & Business Media, p. 93, ISBN 978-1461468004.
^ Zorec, J.; et al. (July 2009), "Fundamental parameters of B supergiants from the BCD system. I. Calibration of the (λ_1, D) parameters into T_eff", Astronomy and Astrophysics, 501 (1): 297–320, arXiv:0903.5134, Bibcode:2009A&A...501..297Z, doi:10.1051/0004-6361/200811147, S2CID 14969137.