Psi2 Orionis

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For other stars with this Bayer designation, see Psi Orionis.
ψ2 Orionis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Orion
Right ascension 05h 26m 50.22929s[1]
Declination +03° 05′ 44.4203″[1]
Apparent magnitude (V) 4.60[2]
Characteristics
Spectral type B2 IV[3] (B1 III + B2 V)[4]
U−B color index −0.94[2]
B−V color index −0.22[2]
Astrometry
Radial velocity (Rv)+12.0[5] km/s
Proper motion (μ) RA: +1.71[1] mas/yr
Dec.: −1.94[1] mas/yr
Parallax (π)2.87 ± 0.68[1] mas
Distanceapprox. 1,100 ly
(approx. 350 pc)
Orbit[6]
Period (P)2.526 d
Eccentricity (e)0.04
Periastron epoch (T)2437685.227 JD
Argument of periastron (ω)
(secondary)		285°
Semi-amplitude (K1)
(primary)		139.1 km/s
Semi-amplitude (K2)
(secondary)		219.0 km/s
Details
ψ2 Ori A
Mass9.85±0.54[3] M☉
Luminosity10,252[3] L☉
Temperature21,150[3] K
Rotational velocity (v sin i)110[7] km/s
Other designations
ψ2 Ori, 30 Orionis, BD+02° 962, HD 35715, HIP 25473, HR 1811, SAO 112775.[8]
Database references
SIMBADdata

Psi2 Orionis a binary star system in the equatorial constellation of Orion. It has an apparent visual magnitude of 4.60,[2] indicating that it is visible to the naked eye. Based upon an annual parallax shift of 2.87 mass, it is roughly 1,100 light years distant from the Sun.

This is a double-lined spectroscopic binary,[4] which means that the individual absorption lines of both components can be discerned. The pair orbit each other with a period of 2.526 days and a low eccentricity of 0.04.[6] The close orbit is causing their mutual gravitational interaction to distort the shapes of the stars, turning this system into an ellipsoidal variable.[9] The inclination of orbital plane is sufficiently low that the two stars form a grazing eclipsing binary. During the eclipse of the primary component, the visual magnitude is reduced by 0.06, whereas the secondary eclipse reduces the magnitude by 0.03.[10]

The combined spectrum of Psi2 Orionis matches that of a B-type subgiant star with a stellar classification of B2 IV.[3] The primary component is an evolved giant star with a class of B1 III, while the secondary is a B-type main sequence star with a classification of B2 V.[4]

References[]

  1. ^ a b c d e 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.
  2. ^ 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.
  3. ^ a b c d e Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355, S2CID 111387483.
  4. ^ a b c 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.
  5. ^ Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", Washington, Carnegie Institute of Washington, D.C., Bibcode:1953GCRV..C......0W.
  6. ^ a b Pourbaix, D.; et al. (2004), "SB9: 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.
  7. ^ 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.
  8. ^ "psi02 Ori". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-12-01.{{cite web}}: CS1 maint: postscript (link)
  9. ^ Beech, Martin (February 1989), "The ellipsoidal variables. IV - Light variations", Astrophysics and Space Science, 152 (2): 329–335, Bibcode:1989Ap&SS.152..329B, doi:10.1007/BF00636314, S2CID 119488926.
  10. ^ Lefèvre, L.; et al. (2009), "A systematic study of variability among OB-stars based on HIPPARCOS photometry", Astronomy and Astrophysics, 507 (2): 1141–1201, Bibcode:2009A&A...507.1141L, doi:10.1051/0004-6361/200912304, ISSN 0004-6361.
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