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]
The primary (θ Scorpii A) is an
evolvedbright giant star with a
stellar classification of F0 II.[3] With a mass 3.10 times that
of the Sun, it is radiating 1,400[6] times as much luminosity
as the Sun from its
outer envelope at an
effective temperature of 6,294 K,[6] 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 19% larger than the polar radius.[9] 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.[6]
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.[6]
^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.
^
abHouk, Nancy (1978). "Michigan catalogue of two-dimensional spectral types for the HD stars". Ann Arbor: Dept. Of Astronomy. 2. Ann Arbor: Departement of Astronomy, University of Michigan.
Bibcode:
1978mcts.book.....H.
^
abcJohnson, 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.
^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.
^
abcdefghijLewis, 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.
^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.
ISBN978-1-931559-44-7.
^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].