Theta Scorpii

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Template:Short description

Theta Scorpii
Observation data
Epoch J2000      Equinox J2000
Constellation Scorpius
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 1.84 (1.862 + 6.22)[2]
Characteristics
Evolutionary stage Post-stellar merger[3]
Spectral type F1III[4]
U−B color index +0.21[5]
B−V color index +0.40[5]
Astrometry
Radial velocity (Rv)+1.4[6] km/s
Proper motion (μ) RA: +5.54[1] mas/yr
Dec.: −3.12[1] mas/yr
Parallax (π)9.90±0.26 mas[3]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)−2.71[7]
Details
Mass3.10+0.37
−0.32[3] M☉
Radius35.5 (equatorial)
26.3 (polar)[3] R☉
Luminosity1,400[3] L☉
Surface gravity (log g)2.4±0.2[8] cgs
Temperature6,294[3] K
Rotation16.60[3] days
Rotational velocity (v sin i)125[9] km/s
Other designations
Template:Odlist[10]
Database references
SIMBADdata

Theta Scorpii (θ Scorpii, abbreviated Theta Sco, θ Sco) is a binary star in the southern zodiac constellation of Scorpius. The apparent visual magnitude of this star is +1.87,[5] making it readily visible to the naked eye and one of the brightest stars in the night sky. It is sufficiently near that the distance can be measured directly using the parallax technique and such measurements obtained during the Hipparcos mission yield an estimate of approximately 329 light-years (101 parsecs) from the Sun.

The two components are designated θ Scorpii A (officially named Sargas /ˈsɑːrɡæs/, the traditional name for the system)[11][12] and B.

Nomenclature

θ Scorpii (Latinised to Theta Scorpii) is the system's Bayer designation. The designations of the two components as Theta Scorpii A and B derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[13]

It bore the traditional name Sargas, of Sumerian origin.[14] Another possible origin is Persian for Arrow Head سر گز. The name 'Sar Gaz' is used in Iran as a star name, and was used for timing irrigation water shares.[15] In 2016, the IAU organized a Working Group on Star Names (WGSN)[16] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[17] It approved the name Sargas for the star θ Scorpii A on 21 August 2016 and it is now so included in the List of IAU-approved Star Names.[12]

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Tail, refers to an asterism consisting of Theta Scorpii, Epsilon Scorpii, Zeta1 Scorpii and Zeta2 Scorpii, Eta Scorpii, Iota1 Scorpii and Iota2 Scorpii, Kappa Scorpii, Lambda Scorpii, Mu1 Scorpii and Upsilon Scorpii.[18] Consequently, the Chinese name for Theta Scorpii itself is Script error: No such module "Lang". (Script error: No such module "Lang".), "the Fifth Star of Tail".[19]

Properties

The primary (θ Scorpii A) has a stellar classification of F1 III, with a luminosity class III indicating its luminosity is comparable to that of a F-type giant.[4] With a mass 3.10 times that of the Sun, it is radiating 1,400[3] times as much luminosity as the Sun from its outer envelope at an effective temperature of 6,294 K,[3] giving it the yellow-white-hued glow of an F-type star. This star is rotating rapidly, giving it an oblate shape with an equatorial radius 33% larger than the polar radius. The equatorial radius is about 36 R☉ while the polar radius is only about 26 R☉. This rapid rotation suggests that it formed via the merger of a binary star system.[3]

A magnitude 5.36 companion has been reported at an angular separation of 6.470 arcseconds,[20] but subsequent observers have failed to detect it, so it probably does not exist. However, a secondary, designated θ Scorpii B, has been detected at an angular separation of 0.538 arcseconds in 1991 by the Hipparcos satellite.[3]

Modern legacy

Theta Scorpii appears on the flag of Brazil, symbolising the state of Alagoas.[21]

References

  1. ^ a b c d Page Module:Citation/CS1/styles.css has no content.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. ^ Page Module:Citation/CS1/styles.css has no content.Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27. Bibcode:2000A&A...355L..27H. doi:10.1888/0333750888/2862.
  3. ^ a b c d e f g h i j k Page Module:Citation/CS1/styles.css has no content.Lewis, Fiona; Bailey, Jeremy; Cotton, Daniel V.; Howarth, Ian D.; Kedziora-Chudczer, Lucyna; Van Leeuwen, Floor (2022). "A study of the F-giant star θ Scorpii A: A post-merger rapid rotator?". Monthly Notices of the Royal Astronomical Society. 513 (1): 1129–1140. arXiv:2204.02719. Bibcode:2022MNRAS.513.1129L. doi:10.1093/mnras/stac991.
  4. ^ a b Page Module:Citation/CS1/styles.css has no content.Keenan, Philip C.; McNeil, Raymond C. (October 1989). "The Perkins Catalog of Revised MK Types for the Cooler Stars". The Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373. ISSN 0067-0049.
  5. ^ a b c Page Module:Citation/CS1/styles.css has no content.Johnson, H. L.; et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99): 99. Bibcode:1966CoLPL...4...99J.
  6. ^ Page Module:Citation/CS1/styles.css has no content.Wilson, R. E. (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Carnegie Institute of Washington D.C. Bibcode:1953GCRV..C......0W.
  7. ^ Page Module:Citation/CS1/styles.css has no content.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.
  8. ^ Page Module:Citation/CS1/styles.css has no content.Samedov, Z. A. (1988). "Investigation of the atmospheres of the stars ι1 Sco (F2 Ia) and θ Sco (F1 II)". Astrophysics. 28 (3): 335–341. Bibcode:1988Ap.....28..335S. doi:10.1007/BF01112969. S2CID 119828317.
  9. ^ Page Module:Citation/CS1/styles.css has no content.van Belle, Gerard T. (March 2012). "Interferometric observations of rapidly rotating stars". The Astronomy and Astrophysics Review. 20 (1) 51. arXiv:1204.2572. Bibcode:2012A&ARv..20...51V. doi:10.1007/s00159-012-0051-2. S2CID 119273474.
  10. ^ Page Module:Citation/CS1/styles.css has no content."* tet Sco". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-02-18. {{cite web}}: Invalid |mode=Script error: No such module "Citation mode". (help)
  11. ^ Page Module:Citation/CS1/styles.css has no content.Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
  12. ^ a b Page Module:Citation/CS1/styles.css has no content."Naming Stars". IAU.org. Retrieved 3 March 2018.
  13. ^ Page Module:Citation/CS1/styles.css has no content.Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
  14. ^ Page Module:Citation/CS1/styles.css has no content.Burnham, Robert (1978). Burnham's celestial handbook: an observer's guide to the universe beyond the solar system. Dover books explaining science. Vol. 3 (2nd ed.). Courier Dover Publications. p. 1676. ISBN 0-486-23673-0.
  15. ^ Page Module:Citation/CS1/styles.css has no content.Nash, Harriet; et al. (2012). Traditional Timing of Qanat Water Shares. International Conference on Traditional Knowledge for Water. Retrieved 26 April 2017.
  16. ^ Page Module:Citation/CS1/styles.css has no content."IAU Working Group on Star Names (WGSN)". International Astronomical Union. Retrieved 22 May 2016.
  17. ^ Page Module:Citation/CS1/styles.css has no content."WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
  18. ^ Template:In lang 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, Template:ISBN.
  19. ^ Template:In lang 香港太空館 - 研究資源 - 亮星中英對照表 Script error: No such module "webarchive"., Hong Kong Space Museum. Accessed on line November 23, 2010.
  20. ^ Page Module:Citation/CS1/styles.css has no content.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. S2CID 14878976.
  21. ^ Page Module:Citation/CS1/styles.css has no content."Astronomy of the Brazilian Flag". Flags of the World.

Template:Stars of Scorpius

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