Gamma Sagittae
Red giant star in the constellation Sagitta
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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 â34 km/s.[7]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Sagitta |
| Right ascension | 19h 58m 45.42823s[1] |
| Declination | +19° 29â² 31.7261â³[1] |
| Apparent magnitude (V) | +3.47[2] |
| Characteristics | |
| Evolutionary stage | Red giant branch[3] |
| Spectral type | M0 III[4][5][6] |
| UâB color index | +1.93[2] |
| BâV color index | +1.57[2] |
| Astrometry | |
| Radial velocity (Rv) | â34.0±0.2[7] km/s |
| Proper motion (μ) | RA: +65.005 mas/yr[1] Dec.: +22.72 mas/yr[1] |
| Parallax (Ï) | 11.3375±0.1652 mas[1] |
| Distance | 288 ± 4 ly (88 ± 1 pc) |
| Absolute magnitude (MV) | â1.11[3] |
| Details | |
| Mass | 0.88+0.05 â0.02 Mâ[8] 0.9±0.2 Mâ[9] 1.3±0.4 Mâ[10] 1.77[5] Mâ |
| Radius | 57.71+0.86 â0.88[11] Râ |
| Luminosity (bolometric) | 697±30[12] Lâ |
| Surface gravity (log g) | 1.06±0.04[12] cgs |
| Temperature | 3,904±30[12] K |
| Metallicity [Fe/H] | â0.26±0.06[12] dex |
| Age | 2.35[5] Gyr |
| Other designations | |
| γ Sge, 12 Sagittae, BD+19°4229, FK5 752, GC 27672, HD 189319, HIP 98337, HR 7635, SAO 105500, PPM 137344 | |
| 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[5] billion years old with roughly 58[11] times the Sun's radius. Mass estimates range from 0.9[8][9] to 1.8[5] 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, å·¦æ (ZuÇ QÃ), 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 Ï Aquilae. Consequently, the Chinese name for γ Sagittae itself is å·¦æäº (ZuÇ Qà wÇ, English: the Fifth Star of Left Flag).[16]