# Omega Octantis

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**Omega Octantis**, ([latinized](/source/Romanization_of_Greek) from **ω Octantis**), is a solitary,[1] bluish-white hued [star](/source/Star) located in the southern [circumpolar constellation](/source/Circumpolar_constellation) [Octans](/source/Octans). It has an [apparent magnitude](/source/Apparent_magnitude) of 5.87,[2] allowing it to be faintly seen with the [naked eye](/source/Naked_eye). Based on the object's [parallax](/source/Parallax) measurements, it is estimated to be 328 [light years](/source/Light_year) distant.[3] However, it is drifting closer with a heliocentric [radial velocity](/source/Radial_velocity) -7.6 km/s.[4]

Omega Octantis has a [stellar classification](/source/Stellar_classification) of B9.5 V,[5] indicating that it is a [main-sequence star](/source/Main-sequence_star) between the B9 and A0 classes. [Helmut A. Abt](/source/Helmut_A._Abt) & [Nidia I. Morrell](/source/Nidia_Morrell) gave a slightly updated class of B9.5 Vs,[6] which includes sharp (narrow) [absorption lines](/source/Absorption_lines) in Omega Octantis' [spectrum](/source/Spectrum) due to slow rotation. It has a [mass](/source/Mass) 2.54 times that of the [Sun](/source/Sun)[7] and is calculated to be 197 [million years](/source/Million_years) old,[8] having completed 40% of its [main sequence](/source/Main_sequence) lifetime.[7] It has a [luminosity](/source/Luminosity) of ,[7] which comes from a [radius](/source/Radius) of and an [effective temperature](/source/Effective_temperature) of 10,759 K. In 2012, George A. Gontcharov calculated a solar [metallicity](/source/Metallicity) for Omega Octantis,[9] and it is spinning modestly with a [projected rotational velocity](/source/Projected_rotational_velocity) of 36 km/s.[10] The slow rotation is consistent with the spectral classification from Abt & Morell (1995).[6]

## References

1. Eggleton, P. P. & Tokovinin, A. A. (11 September 2008). "A catalogue of multiplicity among bright stellar systems". *Monthly Notices of the Royal Astronomical Society*. **389** (2): 869–879. [arXiv:0806.2878](https://arxiv.org/abs/0806.2878). [Bibcode:2008MNRAS.389..869E](https://ui.adsabs.harvard.edu/abs/2008MNRAS.389..869E). [doi:10.1111/j.1365-2966.2008.13596.x](https://doi.org/10.1111/j.1365-2966.2008.13596.x). [ISSN 0035-8711](https://www.worldcat.org/issn/0035-8711)

1. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". *Astronomy and Astrophysics*. **355**: L27–L30. [Bibcode:2000A&A...355L..27H](https://ui.adsabs.harvard.edu/abs/2000A%26A...355L..27H). [ISSN 0004-6361](https://www.worldcat.org/issn/0004-6361)

1. 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](https://arxiv.org/abs/1606.08053). [Bibcode:2006AstL...32..759G](https://ui.adsabs.harvard.edu/abs/2006AstL...32..759G). [doi:10.1134/S1063773706110065](https://doi.org/10.1134/S1063773706110065). [ISSN 1063-7737](https://www.worldcat.org/issn/1063-7737). [S2CID 119231169](https://api.semanticscholar.org/CorpusID:119231169)

1. Houk, N. & Cowley, A. P. (1975). *University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations −90° to −53°*. [Bibcode:1975mcts.book.....H](https://ui.adsabs.harvard.edu/abs/1975mcts.book.....H)

1. Abt, Helmut A. & Morrell, Nidia I. (July 1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". *The Astrophysical Journal Supplement Series*. **99**: 135. [Bibcode:1995ApJS...99..135A](https://ui.adsabs.harvard.edu/abs/1995ApJS...99..135A). [doi:10.1086/192182](https://doi.org/10.1086/192182). [ISSN 0067-0049](https://www.worldcat.org/issn/0067-0049)

1. Zorec, J. & Royer, F. (January 2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". *Astronomy and Astrophysics*. **537**: A120. [arXiv:1201.2052](https://arxiv.org/abs/1201.2052). [Bibcode:2012A&A...537A.120Z](https://ui.adsabs.harvard.edu/abs/2012A%26A...537A.120Z). [doi:10.1051/0004-6361/201117691](https://doi.org/10.1051/0004-6361/201117691). [ISSN 0004-6361](https://www.worldcat.org/issn/0004-6361). [S2CID 55586789](https://api.semanticscholar.org/CorpusID:55586789)

1. David, Trevor J. & Hillenbrand, Lynne A. (12 May 2015). "The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". *The Astrophysical Journal*. **804** (2): 146. [arXiv:1501.03154](https://arxiv.org/abs/1501.03154). [Bibcode:2015ApJ...804..146D](https://ui.adsabs.harvard.edu/abs/2015ApJ...804..146D). [doi:10.1088/0004-637X/804/2/146](https://doi.org/10.1088/0004-637X/804/2/146)

1. Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". *Astronomy Letters*. **38** (12): 771–782. [arXiv:1606.08814](https://arxiv.org/abs/1606.08814). [Bibcode:2012AstL...38..771G](https://ui.adsabs.harvard.edu/abs/2012AstL...38..771G). [doi:10.1134/S1063773712120031](https://doi.org/10.1134/S1063773712120031). [ISSN 0320-0108](https://www.worldcat.org/issn/0320-0108). [S2CID 118345778](https://api.semanticscholar.org/CorpusID:118345778)

1. Levato, H. & Grosso, M. (June 2004). "New Projected Rotational Velocities of All Southern B-type Stars of the Bright Star Catalogue". *Astronomical Society of the Pacific*. **215**: 51. [Bibcode:2004IAUS..215...51L](https://ui.adsabs.harvard.edu/abs/2004IAUS..215...51L)

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Adapted from the Wikipedia article [Omega Octantis](https://en.wikipedia.org/wiki/Omega_Octantis) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Omega_Octantis?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.