Psi2 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 |
| Distance | approx. 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 | |
| Mass | 9.85±0.54[3] M☉ |
| Luminosity | 10,252[3] L☉ |
| Temperature | 21,150[3] K |
| Rotational velocity (v sin i) | 110[7] km/s |
| Other designations | |
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 a 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 2 3 4 5 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. - 1 2 3 4 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.
- 1 2 3 4 5 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.
- 1 2 3 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.
- ↑ Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", Washington, Carnegie Institute of Washington, D.C., Bibcode:1953GCRV..C......0W.
- 1 2 Pourbaix, D.; et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy and Astrophysics, 424 (2): 727, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213.
- ↑ 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.
- ↑ "psi02 Ori -- Variable Star of beta Cep type", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-12-01.
- ↑ 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.
- ↑ 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.