Ω_Carinae

Omega Carinae

Omega Carinae

Star in the constellation Carina

Omega Carinae, Latinized from ω Carinae, is a star in the constellation Carina. With a declination greater than 70 degrees south of the celestial equator, it is the most southerly of the bright stars of Carina (third-magnitude or brighter), and it is part of a southern asterism known as the Diamond Cross. This star has an apparent visual magnitude of 3.3 and is located at a distance of about 342 light-years (105 parsecs) from Earth.

Quick Facts Observation data Epoch J2000 Equinox J2000, Constellation ...

Properties

Omega Carinae has a stellar classification of B8 IIIe,[3] which places it in the category of Be stars, that display emission lines of hydrogen their spectrum. Omega Carinae is a shell star,[3] having a circumstellar disk of gas surrounding its equator. The luminosity class of III indicates it has evolved into a giant star, having exhausted the hydrogen at its core and left the main sequence. The effective temperature of 11,630 K[7] in its outer envelope is what gives this star the blue-white hue that is characteristic of B-type stars.

This star is rotating rapidly with a projected rotational velocity of 240 km/s,[7] which gives a lower limit to the star's azimuthal velocity along the equator. The critical equatorial velocity, at which the star would begin to break up, is 320 km s−1. The star's axis of rotation is inclined by an estimated angle of 70.8° to the line of sight from the Earth.[9]

In the next 7500 years, the south Celestial pole will pass close to this star (AD 5800) and then I Carinae.[10]

In culture

In Chinese, 南船 (Nán Chuán), meaning Southern Boat, refers to an asterism consisting of ω Carinae, V337 Carinae, PP Carinae, θ Carinae and β Carinae .[11] Consequently, ω Carinae itself is known as 南船四 (Nán Chuán sì, English: the Fourth Star of Southern Boat.)[12]

References

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    van Leeuwen, F. (November 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
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    Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W
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    Rivinius, Th.; Štefl, S.; Baade, D. (November 2006), "Bright Be-shell stars", Astronomy and Astrophysics, 459 (1): 137–145, Bibcode:2006A&A...459..137R, doi:10.1051/0004-6361:20053008
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    Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement, 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168
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    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, S2CID 119257644
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    Arcos, C.; Kanaan, S.; Chávez, J.; Vanzi, L.; Araya, I.; Curé, M. (2018), "Stellar parameters and H α line profile variability of be stars in the BeSOS survey", Monthly Notices of the Royal Astronomical Society, 474 (4): 5287, arXiv:1711.08675, Bibcode:2018MNRAS.474.5287A, doi:10.1093/mnras/stx3075
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    Zorec, J.; Frémat, Y.; Domiciano De Souza, A.; Royer, F.; Cidale, L.; Hubert, A. -M.; Semaan, T.; Martayan, C.; Cochetti, Y. R.; Arias, M. L.; Aidelman, Y.; Stee, P. (2016), "Critical study of the distribution of rotational velocities of be stars. I. Deconvolution methods, effects due to gravity darkening, macroturbulence, and binarity", Astronomy and Astrophysics, 595: A132, Bibcode:2016A&A...595A.132Z, doi:10.1051/0004-6361/201628760, hdl:11336/37946
  8. [8]
    "ome Car -- Be Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-01-13
  9. [9]
    Frémat, Y.; et al. (September 2005), "Effects of gravitational darkening on the determination of fundamental parameters in fast-rotating B-type stars", Astronomy and Astrophysics, 440 (1): 305–320, arXiv:astro-ph/0503381, Bibcode:2005A&A...440..305F, doi:10.1051/0004-6361:20042229, S2CID 19016751
  10. [10]
    Kieron Taylor (2005), "Precession", moonkmft, retrieved 2020-01-19
  11. [11]
    (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  12. [12]
    (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 28 日
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