Chi Sagittarii

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The Bayer designation Chi Sagittarii (χ Sagittarii) is shared by three star systems in the zodiac constellation of Sagittarius. The brightest of these, χ1 Sagittarii and χ3 Sagittarii, are separated by 0.56° on the sky. The dimmer star χ2 Sagittarii is located between them, 0.10° from χ1, and is too faint to be seen with the naked eye. In 1977, the Wow! signal came from the direction of these stars.

Name and etymology[edit]

These three χ star, together with φ Sgr, σ Sgr, ζ Sgr and τ Sgr were Al Naʽām al Ṣādirah (النعم السادرة), the Returning Ostriches.[1] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Naʽām al Ṣādirah or Namalsadirah was originally the title for four stars: φ Sgr as Namalsadirah I, τ Sgr as Namalsadirah II, χ1 Sgr as Namalsadirah III and χ2 Sgr as Namalsadirah IV (except σ Sgr and ζ Sgr).[2] In Chinese, (Gǒu), meaning Dog, refers to an asterism consisting of χ1 Sagittarii and 52 Sagittarii. Consequently, χ1 Sagittarii itself is known as 狗二 (Gǒu èr, English: the Second Star of Dog.)[3]


  1. ^ 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.
  2. ^ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF), California Institute of Technology: Jet Propulsion Laboratory, retrieved 2017-07-05.
  3. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 2 日