Delta Sagittarii

Delta Sagittarii
Diagram showing star positions and boundaries of the Sagittarius constellation and its surroundings


Location of δ Sagittarii (circled)

Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Sagittarius
Right ascension 18h 20m 59.64354s[1]
Declination −29° 49′ 41.1659″[1]
Apparent magnitude (V) +2.70[2]
Characteristics
Spectral type K3 III[3]
U−B color index +1.55[2]
B−V color index +1.38[2]
Astrometry
Radial velocity (Rv)–19.9[4] km/s
Proper motion (μ) RA: +32.54[1] mas/yr
Dec.: −25.57[1] mas/yr
Parallax (π)9.38 ± 0.18[1] mas
Distance348 ± 7 ly
(107 ± 2 pc)
Absolute magnitude (MV)−1.99[5]
Details
Other designations
Kaus Media, Kaus Meridionalis, Media, δ Sagittarii, δ Sgr, Delta Sgr, 19 Sagittarii, CCDM J18210-2950A, CPD-30 5513, FK5 687, GC 25024, HD 168454, HIP 89931, HR 6859, IDS 18146-2952 A, PPM 268275, SAO 186681, WDS J18210-2950A.[6]

Delta Sagittarii (δ Sagittarii, abbreviated Delta Sgr, δ Sgr), also named Kaus Media,[7] is a double star[6] in the southern zodiac constellation of Sagittarius. The apparent visual magnitude of this star is +2.70,[2] making it easily visible to the naked eye. Parallax measurements place the distance at roughly 348 light-years (107 parsecs) from the Sun.[1]

Properties

Delta Sagittarii is a giant star with a stellar classification K3 III.

It has three dim companions:[8]

It is not certain that these stars form a physical system or whether they are merely aligned by chance.

Nomenclature

δ Sagittarii (Latinised to Delta Sagittarii) is the star's Bayer designation.

It bore the traditional names Kaus Media, Kaus Meridionalis, and Media, which derive from the Arabic قوس (qaws, meaning "bow") and Latin media (meaning "middle"). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[9] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[10] included a table of the first two batches of names approved by the WGSN; which included Kaus Media for this star.

In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Thani al Waridah, meaning 'second of Warida'.[11]

In Chinese, 箕 (Jī), meaning Winnowing Basket, refers to an asterism consisting of Delta Sagittarii, Gamma Sagittarii, Epsilon Sagittarii and Eta Sagittarii. Consequently, Delta Sagittarii itself is known as 箕宿二 (Jī Sù èr, English: the Second Star of Winnowing Basket.)[12]

This star, together with Gamma Sagittarii, Epsilon Sagittarii, Zeta Sagittarii, Lambda Sagittarii, Sigma Sagittarii, Tau Sagittarii and Phi Sagittarii, comprise the asterism 'Teapot'.[13][14]

In the Hindu system of astrology, this star is also called Purvashada Nakshatra.

See also

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:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357
  2. 1 2 3 4 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
  3. ↑ Houk, Nancy (1979), "Michigan catalogue of two-dimensional spectral types for the HD stars", Michigan Catalogue of Two-dimensional Spectral Types for the HD stars. Volume_3. Declinations -40_ƒ0 to -26_ƒ0, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, 3, Bibcode:1982mcts.book.....H
  4. ↑ Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick, eds., "The Revision of the General Catalogue of Radial Velocities", Determination of Radial Velocities and their Applications, University of Toronto: International Astronomical Union, 30: 57, Bibcode:1967IAUS...30...57E, retrieved 2009-09-10
  5. ↑ Elgarøy, Øystein; Engvold, Oddbjørn; Lund, Niels (March 1999), "The Wilson-Bappu effect of the MgII K line - dependence on stellar temperature, activity and metallicity", Astronomy and Astrophysics, 343: 222–228, Bibcode:1999A&A...343..222E
  6. 1 2 "del Sgr -- Star in double system", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-01-11
  7. ↑ "IAU Catalog of Star Names". Retrieved 28 July 2016.
  8. ↑ Dommanget, J.; Nys, O. (1994). "Catalogue des composantes d'etoiles doubles et multiples (CCDM) premiere edition - Catalogue of the components of double and multiple stars (CCDM) first edition". Com. de l'Observ. Royal de Belgique. 115: 1. Bibcode:1994CoORB.115....1D.
  9. ↑ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  10. ↑ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016.
  11. ↑ Knobel, E. B. (June 1895). "Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket". Monthly Notices of the Royal Astronomical Society. 55 (8): 435. Bibcode:1895MNRAS..55..429K. doi:10.1093/mnras/55.8.429.
  12. ↑ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 11 日
  13. ↑ "Sagittarius". deepsky.astroinfo.org. Retrieved 30 August 2008.
  14. ↑ skywatchers Archived May 17, 2007, at the Wayback Machine.
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