Omega Sagittarii

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Omega Sagittarii
Diagram showing star positions and boundaries of the Sagittarius constellation and its surroundings
Cercle rouge 100%.svg

Location of ω Sagittarii (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension 19h 55m 50.3577s[1]
Declination −26° 17′ 58.223″[1]
Apparent magnitude (V) 4.70[1]
Spectral type G5IV[1]
U−B color index +0.32[2]
B−V color index +0.75[2]
R−I color index +0.37[2]
Radial velocity (Rv) −21.0 ± 0.9[1] km/s
Proper motion (μ) RA: 203.96[1] mas/yr
Dec.: 74.40[1] mas/yr
Parallax (π) 42.03 ± 0.94[1] mas
Distance 78 ± 2 ly
(23.8 ± 0.5 pc)
Absolute magnitude (MV) 2.82[3]
Radius 1.1[4] R
Temperature 5400[5] K
Metallicity [Fe/H] = 0.00[5]
Rotational velocity (v sin i) 2[5] km/s
Age 2.9 (2.8 to 3.0) × 109[5] years
Other designations
ω Sagittarii, ω Sgr, Omega Sgr, 58 Sgr, CPD−26 6880, GC 27583, HD 188376, HIP 98066, HR 7597, PPM 270451, SAO 188722.[1]
Database references

Omega Sagittarii (Omega Sgr, ω Sagittarii, ω Sgr) is a G-type subgiant star in the constellation of Sagittarius.[1] It has an apparent visual magnitude of approximately 4.70.

Name and etymology[edit]

  • This star, together with :
    • 60 Sgr, 62 Sgr and 59 Sgr, consisting the asterism Terebellum[6] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Terebellum was originally the title for four stars: ω Sgr as Terebellum I, 59 Sgr as Terebellum II, 60 Sgr as Terebellum III and 62 Sgr as Terebellum IV .[7]
    • ν Sgr, ψ Sgr, τ Sgr, 60 Sgr and ζ Sgr were Al Udḥiyy, the Ostrich's Nest.[6]
  • In Chinese, 狗國 (Gǒu Guó), meaning Dog Territory, refers to an asterism consisting of ω Sagittarii, 60 Sgr, 62 Sgr and 59 Sgr. Consequently, ω Sagittarii itself is known as 狗國一 (Gǒu Guó yī, English: the First Star of Dog Territory.)[8]


  1. ^ a b c d e f g h i j LTT 7872 -- High proper-motion Star, database entry, SIMBAD. Accessed on line November 19, 2009.
  2. ^ a b c HR 7597, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line November 19, 2009.
  3. ^ From apparent magnitude and parallax.
  4. ^ HD 188376, database entry, Catalog of Apparent Diameters and Absolute Radii of Stars (CADARS), 3rd edition, L. E. Pasinetti-Fracassini, L. Pastori, S. Covino, and A. Pozzi, CDS ID II/224. Accessed on line November 19, 2009.
  5. ^ a b c d HD 188376, database entry, The Geneva-Copenhagen Survey of Solar neighbourhood, J. Holmberg et al., 2007, CDS ID V/117A. Accessed on line November 19, 2009.
  6. ^ a b Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York: Dover Publications Inc. p. 355. ISBN 0-486-21079-0. Retrieved 2012-09-04. 
  7. ^ Jack W. Rhoads - Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institute of Technology; November 15, 1971
  8. ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 2 日