Theta Columbae

θ Columbae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Columba
Right ascension 06h 07m 31.63216s[1]
Declination −37° 15′ 10.5114″[1]
Apparent magnitude (V) 5.02[2]
Characteristics
Spectral type B8 IV[3]
B−V color index −0.11[2]
Astrometry
Radial velocity (Rv)+45.3±1.8[4] km/s
Proper motion (μ) RA: +0.12[1] mas/yr
Dec.: +0.41[1] mas/yr
Parallax (π)4.52 ± 0.16[1] mas
Distance720 ± 30 ly
(221 ± 8 pc)
Absolute magnitude (MV)−1.72[5]
Details
Mass4.13±0.09[6] M☉
Luminosity472[7] L☉
Temperature9,916[7] K
Rotational velocity (v sin i)249[3] km/s
Other designations
Elkurud, θ Col, CD−37° 2609, FK5 2468, HD 42167, HIP 29034, HR 2177, SAO 196514.[8]
Database references
SIMBADdata

Theta Columbae (θ Columbae, abbreviated Theta Col, θ Col), also named Elkurud,[9] is a solitary[10] star in the southern constellation of Columba. It is faintly visible to the naked eye, having an apparent visual magnitude of 5.02.[2] Based upon parallax measurements taken during the Hipparcos mission, it is roughly 720 light-years (220 parsecs) distant from the Sun.[1]

Nomenclature

θ Columbae (Latinised to Theta Columbae) is the star's Bayer designation.

For ancient Arabian astronomers, this star, along with Zeta Canis Majoris, Lambda Canis Majoris, Gamma Columbae, Delta Columbae, Kappa Columbae, Lambda Columbae, Mu Columbae and Xi Columbae, formed Al Ḳurūd (ألقرد al-qird), "the Apes".[11][12] In 2016, the IAU organized a Working Group on Star Names (WGSN)[13] to catalog and standardize proper names for stars. The WGSN approved the name Elkurud for this star on 1 June 2018 and it is now so included in the List of IAU-approved Star Names.[9]

In Chinese, 孫 (Sūn), meaning Grandson, refers to an asterism consisting of Theta Columbae and Kappa Columbae.[14] Consequently, Theta Columbae itself is known as 孫二 (Sūn èr, English: the Second Star of Grandson).[15]

Properties

At its present distance, the visual magnitude of the star is reduced by an interstellar extinction factor of 0.11.[16] It is currently moving away from the Sun with a radial velocity of 45.3 km/s.[4] The star made its closest approach about 4.7 million years ago when it underwent perihelion passage at a distance of 10.9 ly (3.33 pc).[4]

This is an evolving B-type subgiant star with a stellar classification of B8 IV,[3] having recently left the main sequence.[6] It is spinning rapidly with a projected rotational velocity of 249 km/s.[3] The star has an estimated four times the mass of the Sun.[6] It radiates 472 times the solar luminosity from its outer atmosphere at an effective temperature of 9,916 K.[7]

References

  1. 1 2 3 4 5 6 van Leeuwen, F. (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.
  2. 1 2 3 Johnson, H. L.; Iriarte, B.; Mitchell, R. I.; Wisniewskj, W. Z. (1999), "UBVRIJKL photometry of the bright stars", Commission Lunar and Planetary Laboratory, 4: 99, Bibcode:1966CoLPL...4...99J.
  3. 1 2 3 4 Royer, F.; et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics, 393: 897–911, arXiv:astro-ph/0205255, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943.
  4. 1 2 3 Bailer-Jones, C. A. L. (March 2015), "Close encounters of the stellar kind", Astronomy & Astrophysics, 575: 13, arXiv:1412.3648, Bibcode:2015A&A...575A..35B, doi:10.1051/0004-6361/201425221, A35.
  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.
  6. 1 2 3 Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691.
  7. 1 2 3 McDonald, I.; et al. (2012). "Fundamental Parameters and Infrared Excesses of Hipparcos Stars". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–57. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x.
  8. ↑ "tet Col -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-12-23.
  9. 1 2 "Naming Stars". IAU.org. Retrieved 18 June 2018.
  10. ↑ 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  11. ↑ Allen, Richard Hinckley (1963), "Columba Noae, Noah's Dove", Star Names: their Lore and Meaning (Dover ed.).
  12. ↑ Davis Jr., G. A. (October 1944), "The Pronunciations, Derivations, and Meanings of a Selected List of Star Names", Popular Astronomy, 18: 14, Bibcode:1944PA.....52....8D.
  13. ↑ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  14. ↑ (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.
  15. ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 16 日
  16. ↑ Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters, 38 (11): 694–706, arXiv:1606.09028, Bibcode:2012AstL...38..694G, doi:10.1134/S1063773712110035.
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