Alpha Sagittae
| |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Sagitta |
| Right ascension | 19h 40m 05.8s [1] |
| Declination | +18° 00′ 50″ [1] |
| Apparent magnitude (V) | +4.39[2] |
| Characteristics | |
| Evolutionary stage | G1II[2] |
| Astrometry | |
| Radial velocity (Rv) | 1.72 ± 0.16[1] km/s |
| Proper motion (μ) | RA: 15.09 ± 0.16[3] mas/yr Dec.: -19.65 ± 0.15[3] mas/yr |
| Parallax (π) | 7.67 ± 0.24[3] mas |
| Distance | 430 ± 10 ly (130 ± 4 pc) |
| Other designations | |
Alpha Sagittae (Alpha Sge, α Sagittae, α Sge) is a star in the constellation Sagitta. It has the traditional proper name Sham or Alsahm which comes to us from Arabic سهم sahm and means Arrow, the name formerly having been applied to the whole constellation. Alpha Sagittae is the third brightest star and is four times more massive and 340 times brighter than the Sun.[4]
In Chinese, 左旗 (Zuǒ Qí), meaning Left Flag, refers to an asterism consisting of α Sagittae, β Sagittae, δ Sagittae, ζ Sagittae, γ Sagittae, 13 Sagittae, 11 Sagittae, 14 Sagittae and ρ Aquilae. Consequently, α Sagittae itself is known as 左旗一 (Zuǒ Qí yī, English: the First Star of Left Flag.)[5]
α Sge is a yellow bright giant star of apparent magnitude +4.38 and spectral class G1 II about 430 ± 10 light years from Earth. It has a luminosity 340 times that of the Sun with a surface temperature of 5,333 K.[2] The star's radius is roughly 20 times solar (R☉) while its mass is 4 times solar (M☉).
References
- 1 2 3 SIMBAD, Alpha Sagittae (accessed 22 May 2015)
- 1 2 3 Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics 352: 495–507, Bibcode:1999A&A...352..495M
- 1 2 3 van Leeuwen, F. (2007). "Validation of the New Hipparcos Reduction". Astronomy and Astrophysics 474 (2): 653–64. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
- ↑ "Sagitta". TopAstronomer.com. Retrieved 2012-05-23.
- ↑ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 3 日
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