Chi Sagittarii

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The Bayer designation Chi Sagittarii (Chi Sgr, χ Sagittarii, χ Sgr) is shared by three star systems in the constellation Sagittarius. The brightest of these, χ¹ Sagittarii and χ³ Sagittarii, are separated by 0.56° on the sky. The dimmer χ² Sagittarii is located between them, 0.10° from χ¹. The Wow! signal came from the direction of these stars.

χ¹ Sagittarii[edit]

Chi¹ Sagittarii
Diagram showing star positions and boundaries of the Sagittarius constellation and its surroundings
Cercle rouge 100%.svg

Location of χ¹ Sagittari (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Sagittarius
Right ascension 19h 25m 16.5s
Declination -24° 30' 31"
Apparent magnitude (V) +5.02
Absolute magnitude (V) +0.86
Distance 221 ± 17 ly
(68 ± 5 pc)
Spectral type A4IV/V
Other designations
χ¹ Sagittarii, χ¹ Sgr, Chi¹ Sgr, 47 Sagittarii, CCDM J19253-2431AB, CPD-24  6721, GC 26789, HD 182369, HIP 95477, HR 7362, IDS 19192-2442 AB, PPM 269762, SAO 188101, WDS J19253-2431AB.

Chi¹ Sagittarii (Chi¹ Sgr, χ¹ Sagittarii, χ¹ Sgr) is a binary star. The primary is a spectral type A5 dwarf. The companion is approximately 0.12 arcseconds from the primary, putting it about 8 Astronomical Units away. The orbital period is 10.8 years. The combined apparent magnitude of the system is +5.02. It is approximately 220 light years from Earth.


χ² Sagittarii[edit]

Chi² Sagittarii
Diagram showing star positions and boundaries of the Sagittarius constellation and its surroundings
Cercle rouge 100%.svg

Location of χ² Sagittari (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Sagittarius
Right ascension 19h 25m 22.3s
Declination -24° 24' 44"
Apparent magnitude (V) +7.27
Absolute magnitude (V) -0.57
Distance 1200 ± 500 ly
(370 ± 150 pc)
Spectral type B7IV
Other designations
χ² Sagittarii, χ² Sgr, Chi² Sgr, 48 Sagittarii, CPD-24  6722, GC 26793, HD 182391, HIP 95486, PPM 269764, SAO 188102

Chi² Sagittarii (Chi² Sgr, χ² Sagittarii, χ² Sgr) is a spectral type B7 subgiant which has an apparent magnitude of +7.26. It is approximately 1200 light years from Earth.


χ³ Sagittarii[edit]

Chi³ Sagittarii
Diagram showing star positions and boundaries of the Sagittarius constellation and its surroundings
Cercle rouge 100%.svg

Location of χ³ Sagittari (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Sagittarius
Right ascension 19h 25m 29.7s
Declination -23° 57' 44"
Apparent magnitude (V) +5.45
Absolute magnitude (V) -0.50
Distance 506 ± 81 ly
(155 ± 25 pc)
Spectral type K3III
Other designations
χ³ Sagittarii, χ³ Sgr, Chi³ Sgr, 49 Sagittarii, CPD-24  6723, GC 26801, HD 182416, HIP 95503, HR 7363, PPM 269765, SAO 188105,

Chi³ Sagittarii (Chi³ Sgr, χ³ Sagittarii, χ³ Sgr) is a spectral type K3 giant which has an apparent magnitude of +5.45. It is 506 light years from Earth.

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 斗二 (Gǒu èr, English: the Second Star of Dog.)[3]

References[edit]