Omega Leonis
ω Leonis (Latinised as Omega Leonis, abbreviated to ω Leo or Omega Leo), is a star located in the zodiac constellation of Leo. It is visible to the naked eye in the absence of light pollution, with an apparent visual magnitude of about 5.4. The distance to this star, as determined using parallax measurements, is around 108 light years from the Sun. Because of its location close to the ecliptic, it is subject to being obscured by the Moon, and potentially by planets.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Leo |
| Right ascension | 09h 28m 27.39861s[1] |
| Declination | +09° 03′ 24.4255″[1] |
| Apparent magnitude (V) | 5.42[2] (5.69 + 7.28)[3] |
| Characteristics | |
| ω Leo A | |
| Evolutionary stage | main sequence[4] |
| Spectral type | G1 V[5] |
| U−B color index | +0.12[2] |
| B−V color index | +0.60[2] |
| Astrometry | |
| Radial velocity (Rv) | −7.6±0.2[6] km/s |
| Proper motion (μ) | RA: +36.98[1] mas/yr Dec.: +5.78[1] mas/yr |
| Parallax (π) | 30.15 ± 1.45[1] mas |
| Distance | 108 ± 5 ly (33 ± 2 pc) |
| Absolute magnitude (MV) | +2.72[7] |
| Orbit[8] | |
| Period (P) | 42,678.5 days |
| Eccentricity (e) | 0.56 |
| Periastron epoch (T) | 2436769.0 (JD) |
| Argument of periastron (ω) (secondary) | 124.6° |
| Semi-amplitude (K1) (primary) | 2.2 km/s |
| Details | |
| ω Leo A | |
| Mass | 1.35+0.05 −0.03[9] M☉ |
| Luminosity | 6[10] L☉ |
| Surface gravity (log g) | 3.82±0.05[9] cgs |
| Temperature | 5940±85[9] K |
| Metallicity [Fe/H] | 0.02±0.06[9] dex |
| Rotational velocity (v sin i) | 5.1[4] km/s |
| Age | 3.68+0.31 −0.28[9] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a spectroscopic binary star system with an orbital period of 116.8 years and an eccentricity of 0.56.[8] In 2010, speckle interferometry observations showed an angular separation of 738±10 mas between the two components along a position angle of 102.7°±0.6°.[12] The primary is a G-type main sequence star with a spectral classification of G1 V.[5] It has about 35%[9] more mass than the Sun and shines six[10] times as brightly from an outer atmosphere that has an effective temperature of 5940 K.[9] The system is roughly 3.7 billion years old[9] and is a member of the galactic thin disk population.[9]
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.
- Mermilliod, J.-C. (1986), Compilation of Eggen's UBV data, transformed to UBV (unpublished), SIMBAD, Bibcode:1986EgUBV........0M.
- Malkov, O. Yu.; et al. (2012), "Dynamical Masses of a Selected Sample of Orbital Binaries", Astronomy & Astrophysics, 546: 5, Bibcode:2012A&A...546A..69M, doi:10.1051/0004-6361/201219774, A69.
- Schröder, C.; et al. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo" (PDF), Astronomy and Astrophysics, 493 (3): 1099–1107, Bibcode:2009A&A...493.1099S, doi:10.1051/0004-6361:200810377.
- Abt, Helmut A. (January 2009), "MK Classifications of Spectroscopic Binaries", The Astrophysical Journal Supplement, 180 (1): 117–118, Bibcode:2009ApJS..180..117A, doi:10.1088/0067-0049/180/1/117.
- Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065.
- 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.
- 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.
- Ramírez, I.; et al. (September 2012), "Lithium Abundances in nearby FGK Dwarf and Subgiant Stars: Internal Destruction, Galactic Chemical Evolution, and Exoplanets", The Astrophysical Journal, 756 (1): 46, arXiv:1207.0499, Bibcode:2012ApJ...756...46R, doi:10.1088/0004-637X/756/1/46.
- 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.
- "ome Leo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-10-05.
- Prieur, J.-L.; et al. (May 2012), "Speckle observations with PISCO in Merate: XI. Astrometric measurements of visual binaries in 2010", Monthly Notices of the Royal Astronomical Society, 422 (2): 1057–1070, Bibcode:2012MNRAS.422.1057P, doi:10.1111/j.1365-2966.2012.20678.x.