| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 04 52 53.66995 |
| Declination | −05° 27′ 09.6972″ |
| Apparent magnitude (V) | 4.37 |
| Characteristics | |
| Spectral type | A9 IVn |
| U−B color index | +0.12 |
| B−V color index | +0.26 |
| Astrometry | |
| Radial velocity (Rv) | −8.3 km/s |
| Proper motion (μ) | RA: −17.86 mas/yr Dec.: +25.57 mas/yr |
| Parallax (π) | 13.88 ± 0.24 mas |
| Distance | 235 ± 4 ly (72 ± 1 pc) |
| Absolute magnitude (MV) | 0.10 |
| Orbit | |
| Period (P) | 3,057 d |
| Eccentricity (e) | 0.46 |
| Periastron epoch (T) | 2419973.0 JD |
| Argument of periastron (ω) (secondary) | 227° |
| Semi-amplitude (K1) (primary) | 18.1 km/s |
| Details | |
| Radius | 6.7 R☉ |
| Luminosity | 69 L☉ |
| Surface gravity (log g) | 3.4 cgs |
| Temperature | 6,878 K |
| Metallicity | 0.18 dex |
| Rotational velocity (v sin i) | 186 km/s |
| Other designations | |
| ω Eri, BD−05° 1068, 61 Eridani, HD 31109, HIP 22701, HR 1560, SAO 131568. | |
| Database references | |
| SIMBAD | data |
Omega Eridani (ω Eri) is a binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude is 4.37. The distance to this star, as determined by the parallax method, is around 235 light years.
This is a single-lined spectroscopic binary system with an orbital period of 3,057 days (8.4 years) and an eccentricity of 0.46. The primary component is an A-type subgiant star with a stellar classification of A9 IVn, where the 'n' suffix indicates a broad ("nebulous") absorption due to rotation. The projected rotational velocity is 186 km/s. This gives the star an oblate shape with an equator that is 13% wider than the polar radius. The angular size of Omega Eridani is 0.87 mas. At an estimated distance of the star, this yields a physical size of around 6.7 times the radius of the Sun.
References
- ^ 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.
- ^ Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
- ^ Abt, Helmut A.; Morrell, Nidia I. (July 1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182.
- De Bruijne, J. H. J.; Eilers, A.-C. (2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: A61, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347.
- ^ Giridhar, S.; et al. (August 2013), "Identification of metal-poor stars using the artificial neural network", Astronomy & Astrophysics, 556: 11, arXiv:1307.6308, Bibcode:2013A&A...556A.121G, doi:10.1051/0004-6361/201219918, S2CID 118316149, A121.
- Pourbaix, D.; et al. (2004), "SB: 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.
- ^ 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:
- ^ McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
- ^ Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298.
- "* ome Eri -- Spectroscopic binary". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-11-03.
{{cite web}}: CS1 maint: postscript (link) - Abt, Helmut A.; Boonyarak, Chayan (November 2004), "Tidal Effects in Binaries of Various Periods", The Astrophysical Journal, 616 (1): 562–566, Bibcode:2004ApJ...616..562A, doi:10.1086/423795.
- van Belle, Gerard T., Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2, S2CID 119273474.
