Rho Scorpii

ρ Scorpii
Location of ρ Scorpii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Scorpius
Right ascension 15h 56m 53.07624s[1]
Declination −29° 12′ 50.6612″ [1]
Apparent magnitude (V) 3.86[2]
Characteristics
Spectral type B2 IV[3]
U−B color index -0.82[2]
B−V color index -0.20[2]
Astrometry
Radial velocity (Rv)−0.40[4] km/s
Proper motion (μ) RA: −15.68[1] mas/yr
Dec.: −24.88[1] mas/yr
Parallax (π)6.91 ± 0.19[1] mas
Distance470 ± 10 ly
(145 ± 4 pc)
Absolute magnitude (MV)−1.93[5]
Orbit[6]
Period (P)4.0033 d
Eccentricity (e)0.27
Periastron epoch (T)2442178.6060 JD
Argument of periastron (ω)
(secondary)		231°
Semi-amplitude (K1)
(primary)		16.40 km/s
Details
Mass7.94±0.55[3] M☉
Radius5.0[7] R☉
Luminosity (bolometric)3,432[3] L☉
Temperature21,150[3] K
Rotational velocity (v sin i)113[8] km/s
Other designations
Iklil, 5 Scorpii, ADS 9846, CCDM J15569-2913A, FK5 3258, GC 21398, HD 142669, HIP 78104, HR 5928, SAO 183957, CD−28° 11714[9]
Database references
SIMBADdata

Rho Scorpii (ρ Scorpii, abbreviated Rho Sco, ρ Sco) is a double star in the constellation of Scorpius. It has an apparent visual magnitude of +3.87, which is bright enough to be seen with the naked eye. Based upon parallax measurements, it is located approximately 472 light years from the Sun.[1] At that distance, the visual magnitude of the system is reduced by 0.07 due to extinction from interstellar dust.[10] It is a member of the Upper Scorpius OB association.[11]

It has two components, designated Rho Scorpii A and B. Rho Scorpii A is itself a single-lined spectroscopic binary whose components are designated Rho Scorpii Aa (also named Iklil[12]) and Ab.

Nomenclature

ρ Scorpii (Latinised to Rho Scorpii) is the system's Bayer designation. The designations of the three constituents as Rho Scorpii A and B, and those of A's components - Rho Scorpii Aa and Ab - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[13]

In 2016, the IAU organized a Working Group on Star Names (WGSN)[14] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[15] It approved the name Iklil for the component Rho Scorpii Aa on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.[12]

In Chinese, 房宿 (Fáng Xiù), meaning Room, refers to an asterism consisting of Rho Scorpii, Pi Scorpii, Delta Scorpii, Beta¹ Scorpii and Beta² Scorpii.[16] Consequently, ρ Scorpii itself is known as 房宿二 (Fáng Xiù èr), "the Second Star of Room".[17]

Properties

Rho Scorpii A displays the spectrum of blue-white B-type subgiant with a stellar classification of B2 IV.[3] It has an estimated mass nearly 8 times that of the Sun's and shines with 3,432 times the Sun's luminosity.[3] The two constituent stars orbit each other with a period of 4 days and an eccentricity of 0.27.[6]

Rho Scorpii B is a magnitude 12.80 visual companion that lies at an angular separation of 38.40 arcseconds along a position angle of 95°, as of the year 2000.[18]

References

  1. 1 2 3 4 5 6 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.
  2. 1 2 3 Ducati, J. R. (2002), "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system", CDS/ADC Collection of Electronic Catalogues, 2237, Bibcode:2002yCat.2237....0D.
  3. 1 2 3 4 5 6 Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355.
  4. ↑ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E.
  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 Pourbaix, D.; et al. (September 2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy and Astrophysics, 424: 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213.
  7. ↑ Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
  8. ↑ Simón-Díaz, S.; Herrero, A. (2014), "The IACOB project: I. Rotational velocities in northern Galactic O- and early B-type stars revisited. The impact of other sources of line-broadening", Astronomy & Astrophysics, 562: A135, arXiv:1311.3360, Bibcode:2014A&A...562A.135S, doi:10.1051/0004-6361/201322758.
  9. ↑ "rho Sco". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-09-22.
  10. ↑ Shatsky, N.; Tokovinin, A. (January 2002), "The mass ratio distribution of B-type visual binaries in the Sco OB2 association", Astronomy and Astrophysics, 382: 92–103, arXiv:astro-ph/0109456, Bibcode:2002A&A...382...92S, doi:10.1051/0004-6361:20011542.
  11. ↑ Grellmann, R.; et al. (June 2015), "New constraints on the multiplicity of massive young stars in Upper Scorpius", Astronomy & Astrophysics, 578: 11, Bibcode:2015A&A...578A..84G, doi:10.1051/0004-6361/201219577, A84.
  12. 1 2 "Naming Stars". IAU.org. Retrieved 16 December 2017.
  13. ↑ 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. ↑ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  15. ↑ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
  16. ↑ (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.
  17. ↑ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2008-10-25 at the Wayback Machine., Hong Kong Space Museum. Accessed on line November 23, 2010.
  18. ↑ Mason, B. D.; et al. (2014), The Washington Visual Double Star Catalog, Bibcode:2001AJ....122.3466M, doi:10.1086/323920
  • Kaler, James B. (June 20, 2008), "Rho Scorpii", Stars, University of Illinois, retrieved 2016-09-23.
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