Gamma Sagittae, Latinized from γ Sagittae, is the brightest star in northern constellation of Sagitta. A single star,[15] 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. 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 45.42863s[1] |
Declination | +19° 29′ 31.7281″[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: 66.21±0.14[1] mas/yr Dec.: 22.22±0.12[1] mas/yr |
Parallax (π) | 11.3375 ± 0.1652 mas[7] |
Distance | 288 ± 4 ly (88 ± 1 pc) |
Absolute magnitude (MV) | −1.11[8] |
Details | |
Mass | 0.88+0.05 −0.02 M☉[9] 0.9±0.2 M☉[10] 1.3±0.4 M☉[11] 1.37±2.00 M☉[12] 1.77[4] M☉ |
Radius | 55.13±3.29[13] R☉ |
Luminosity (bolometric) | 562±75[13] L☉ |
Surface gravity (log g) | 1.71[14] cgs |
Temperature | 3,862±40[4] K |
Metallicity [Fe/H] | −0.14[13] 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.[11][16] It is most likely (94% chance) on the red-giant branch of its evolutionary lifespan, fusing hydrogen along a shell to generate energy.[9][12] The star is around 2.35[4] billion years old with roughly 55[13] times the Sun's radius. Mass estimates range from 0.9[9][10] to 1.8[4] times the mass of the Sun. It is radiating about 562[13] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,862 K.[4]
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).[17]