Gamma Sagittae

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.^[7]

γ Sagittae

Location of γ Sagittae (circled)
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 branch[3]
Spectral type	M0 III[4][5][6]
U−B color index	+1.93[2]
B−V color index	+1.57[2]
Astrometry
Radial velocity (Rv)	−34.0±0.2[7] 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[3]
Details
Mass	0.88+0.05 −0.02 M☉[8] 0.9±0.2 M☉[9] 1.3±0.4 M☉[10] 1.77[5] 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[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, 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]