Gamma Sagittae
Red giant star in the constellation Sagitta From Wikipedia, the free encyclopedia
Gamma Sagittae, Latinized from γ Sagittae, is the brightest star in northern constellation of Sagitta. A single star,[13] it is visible to the naked eye with an apparent visual magnitude of +3.47.[2] Based upon an annual parallax shift of 12.62 mas as seen from Earth, it is located about 288 light-years from the Sun.[1] It is moving closer to the Sun with a radial velocity of −34 km/s.[6]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Sagitta |
| Right ascension | 19h 58m 45.42823s[1] |
| Declination | +19° 29′ 31.7261″[1] |
| Apparent magnitude (V) | +3.47[2] |
| Characteristics | |
| Evolutionary stage | Red giant |
| Spectral type | M0 III[3][4][5] |
| U−B color index | +1.93[2] |
| B−V color index | +1.57[2] |
| Astrometry | |
| Radial velocity (Rv) | −34.0±0.2[6] km/s |
| Proper motion (μ) | RA: +65.005 mas/yr[1] Dec.: +22.72 mas/yr[1] |
| Parallax (π) | 11.3375 ± 0.1652 mas[1] |
| Distance | 288 ± 4 ly (88 ± 1 pc) |
| Absolute magnitude (MV) | −1.11[7] |
| Details | |
| Mass | 0.88+0.05 −0.02 M☉[8] 0.9±0.2 M☉[9] 1.3±0.4 M☉[10] 1.77[4] M☉ |
| Radius | 57.71+0.86 −0.88[11] R☉ |
| Luminosity (bolometric) | 697±30[12] L☉ |
| Surface gravity (log g) | 1.06±0.04[12] cgs |
| Temperature | 3,904±30[12] K |
| Metallicity [Fe/H] | −0.26±0.06[12] dex |
| Age | 2.35[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a red giant star with a stellar classification of M0 III.[10][14] It is most likely (94% chance) on the red-giant branch of its evolutionary lifespan, fusing hydrogen along a shell to generate energy.[8][15] The star is around 2.35[4] billion years old with roughly 58[11] times the Sun's radius. Mass estimates range from 0.9[8][9] to 1.8[4] times the mass of the Sun. It is radiating nearly 700 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,904 K.[12]
Naming
In Chinese, 左旗 (Zuǒ Qí), meaning Left Flag, refers to an asterism consisting of γ Sagittae, α Sagittae, β Sagittae, δ Sagittae, ζ Sagittae, 13 Sagittae, 11 Sagittae, 14 Sagittae and ρ Aquilae. Consequently, the Chinese name for γ Sagittae itself is 左旗五 (Zuǒ Qí wǔ, English: the Fifth Star of Left Flag).[16]
References
External links
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