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Omega Carinae

From Wikipedia, the free encyclopedia
ωおめが Carinae
Location of ωおめが Carinae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Carina
Right ascension 10h 13m 44.21739s[1]
Declination –70° 02′ 16.4563″[1]
Apparent magnitude (V) 3.29[2]
Characteristics
Spectral type B8 IIIe[3]
U−B color index –0.285[4]
B−V color index –0.083[4]
Astrometry
Radial velocity (Rv)+7.0[2] km/s
Proper motion (μみゅー) RA: -36.01[1] mas/yr
Dec.: +7.09[1] mas/yr
Parallax (πぱい)9.54 ± 0.09 mas[1]
Distance342 ± 3 ly
(104.8 ± 1.0 pc)
Absolute magnitude (MV)−1.81[5]
Details
Radius7.20±0.14[6] R
Luminosity918[7] L
Surface gravity (log g)3.51[7] cgs
Temperature11,630[7] K
Rotational velocity (v sin i)240[7] km/s
Other designations
ωおめが Car, CD−69°1178, FK5 385, HD 89080, HIP 50099, HR 4037, SAO 250885[8]
Database references
SIMBADdata

Omega Carinae, Latinized from ωおめが 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.

Properties

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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

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In Chinese, みなみせん (Nán Chuán), meaning Southern Boat, refers to an asterism consisting of ωおめが Carinae, V337 Carinae, PP Carinae, θしーた Carinae and βべーた Carinae .[11] Consequently, ωおめが Carinae itself is known as みなみせんよん (Nán Chuán sì, English: the Fourth Star of Southern Boat.)[12]

References

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  1. ^ a b c d e 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
  2. ^ a b 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
  3. ^ a b c 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
  4. ^ a b 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
  5. ^ 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
  6. ^ Arcos, C.; Kanaan, S.; Chávez, J.; Vanzi, L.; Araya, I.; Curé, M. (2018), "Stellar parameters and H αあるふぁ 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
  7. ^ a b c d e f 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. ^ "ome Car -- Be Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-01-13
  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. ^ Kieron Taylor (2005), "Precession", moonkmft, retrieved 2020-01-19
  11. ^ (in Chinese) 中國ちゅうごく星座せいざ神話しんわ, written by ひね久金ひさがね. Published by 台灣たいわん書房しょぼう出版しゅっぱん有限ゆうげん公司こうし, 2005, ISBN 978-986-7332-25-7.
  12. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文てんもん教育きょういく訊網 2006 ねん 7 がつ 28 にち
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