Astronomy:Theta Octantis
  | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Octans |
| Right ascension | 00h 01m 35.70158s[1] |
| Declination | −77° 03′ 56.6092″[1] |
| Apparent magnitude (V) | 4.78[2] |
| Characteristics | |
| Spectral type | K3III[3] |
| U−B color index | +1.41[4] |
| B−V color index | +1.27[4] |
| Astrometry | |
| Radial velocity (Rv) | +22.48±0.17[5] km/s |
| Proper motion (μ) | RA: −57.30[1] mas/yr Dec.: −177.06[1] mas/yr |
| Parallax (π) | 15.02 ± 0.18[1] mas |
| Distance | 217 ± 3 ly (66.6 ± 0.8 pc) |
| Absolute magnitude (MV) | 0.66[2] |
| Details | |
| Mass | 1.20[6] M☉ |
| Radius | 15.84+0.42 −1.02[5] R☉ |
| Luminosity | 79.2±1.5[5] L☉ |
| Surface gravity (log g) | 2.16[6] cgs |
| Temperature | 4,325+147 −55[5] K |
| Rotational velocity (v sin i) | < 1.0[7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
θ Octantis, Latinized as Theta Octantis, is a single[9] star in the southern circumpolar constellation of Octans, near the constellation border with Hydrus. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.78.[2] The star is located approximately 217 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +22.5 km/s.[5]
This is an aging giant star with a stellar classification of K3III,[3] having exhausted the supply of hydrogen at its core then cooled and expanded. It has been catalogued as a red clump giant,[10] which would indicate it is on the horizontal branch and is undergoing core helium fusion. At present it has 16[5] times the radius of the Sun. This star has 1.20[6] times the mass of the Sun and is radiating 79[5] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,325 K.[5]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (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.
- ↑ 2.0 2.1 2.2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. Vizier catalog entry
- ↑ 3.0 3.1 Houk, Nancy; Cowley, A. P. (1979). Michigan catalogue of two-dimensional spectral types for the HD stars. 1. Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan. Bibcode: 1978mcts.book.....H.
- ↑ 4.0 4.1 Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers 42 (2): 443. Bibcode: 2014JAVSO..42..443M. Vizier catalog entry
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 6.0 6.1 6.2 Allende Prieto, C.; Lambert, D. L. (1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: Masses, radii and effective temperatures". Astronomy and Astrophysics 352: 555–562. Bibcode: 1999A&A...352..555A. Vizier catalog entry
- ↑ De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (2014). "A catalog of rotational and radial velocities for evolved stars". Astronomy & Astrophysics 561: A126. doi:10.1051/0004-6361/201220762. Bibcode: 2014A&A...561A.126D. Vizier catalog entry
- ↑ "tet Oct". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=tet+Oct.
- ↑ 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.
- ↑ Gontcharov, G. A. (2009). "Red giant clump in the Tycho-2 catalogue". Astronomy Letters 34 (11): 785–796. doi:10.1134/S1063773708110078. Bibcode: 2008AstL...34..785G. Vizier catalog entry
 |  |
