Chi Sagittarii
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
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| 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 | |
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
|
|
| 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 | |
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
|
|
| 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 | |
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
- 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, 狗 (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]
References
- ↑ 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.
- ↑ 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
- ↑ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 2 日