Astronomy:Theta Antliae
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Antlia[1] |
| Right ascension | 09h 44m 12.09512s[2] |
| Declination | −27° 46′ 10.1011″[2] |
| Apparent magnitude (V) | 4.79[3] |
| Characteristics | |
| Spectral type | A8 Vm + G7 III[4] |
| U−B color index | +0.35[3] |
| B−V color index | +0.50[3] |
| Astrometry | |
| Radial velocity (Rv) | +24.0[5] km/s |
| Proper motion (μ) | RA: −53.23[2] mas/yr Dec.: +37.24[2] mas/yr |
| Parallax (π) | 9.61 ± 0.46[2] mas |
| Distance | 340 ± 20 ly (104 ± 5 pc) |
| Absolute magnitude (MV) | −0.30[1] |
| Orbit[6] | |
| Companion | θ Ant B |
| Period (P) | 18.266±0.185 yr |
| Semi-major axis (a) | 0.110±0.002″ |
| Eccentricity (e) | 0.404±0.005 |
| Inclination (i) | 123.6±1.0° |
| Longitude of the node (Ω) | 3.5±1.0° |
| Periastron epoch (T) | 2020.143±0.200 |
| Argument of periastron (ω) (secondary) | 141.2±3.0° |
| Details[6] | |
| θ Ant A | |
| Mass | 1.8±0.1 M☉ |
| θ Ant B | |
| Mass | 2.1±0.5 M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
Theta Antliae is a binary star system in the southern constellation of Antlia. Its identifier is a Bayer designation that was Latinized from θ Antliae, and is abbreviated Tet Ant or θ Ant, respectively. The pair have a combined apparent visual magnitude of +4.78,[3] which is bright enough to be faintly visible to the naked eye. The brighter component is magnitude +5.30 while the secondary is +6.18.[8] Based upon parallax measurements, it is located at a distance of around 340 light-years (104 parsecs) from Earth. The system is receding with a heliocentric radial velocity of +24 km/s.[5]
The binary nature of this system was discovered by W. S. Finsen in 1952.[6] The primary component of this system, θ Antliae A, has a stellar classification of A8 Vm,[4] indicating that it is an A-type main sequence star with enhanced metallic lines in its spectrum. The companion, θ Antliae B, is a giant star with a classification of G7 III.[4] The pair have an orbital period of 18.3 years, a significant eccentricity of 0.4, and an angular separation of 0.1 arcseconds.[6]
References
- ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 2.0 2.1 2.2 2.3 2.4 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 3.0 3.1 3.2 3.3 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J.
- ↑ 4.0 4.1 4.2 Ginestet, N.; Carquillat, J. M. (December 2002), "Spectral Classification of the Hot Components of a Large Sample of Stars with Composite Spectra, and Implication for the Absolute Magnitudes of the Cool Supergiant Components", The Astrophysical Journal Supplement Series 143 (2): 513–537, doi:10.1086/342942, Bibcode: 2002ApJS..143..513G.
- ↑ 5.0 5.1 Wilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities", Washington (Carnegie Institution of Washington), Bibcode: 1953GCRV..C......0W.
- ↑ 6.0 6.1 6.2 6.3 Docobo, J. A.; Andrade, M. (January 2013), "Dynamical and physical properties of 22 binaries discovered by W. S. Finsen", Monthly Notices of the Royal Astronomical Society 428 (1): 321–339, doi:10.1093/mnras/sts045, Bibcode: 2013MNRAS.428..321D.
- ↑ "tet Ant". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=tet+Ant.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
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