Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
---|---|
Constellation | Sagitta |
Right ascension | 19h 37m 17.39324s [1] |
Declination | +16° 27′ 46.0871″ [1] |
Apparent magnitude (V) | +5.64 to +5.67 [2] |
Characteristics | |
Spectral type | G8 IIIvar [3] |
U−B color index | +0.83 [4] |
B−V color index | +1.00 [4] |
Astrometry | |
Radial velocity (Rv) | −32.49±0.18 [1] km/s |
Proper motion (μ) |
RA: +16.382±0.164
[1]
mas/
yr Dec.: +14.364±0.135 [1] mas/ yr |
Parallax (π) | 5.6067 ± 0.1173 mas [1] |
Distance | 580 ± 10
ly (178 ± 4 pc) |
Absolute magnitude (MV) | −0.84±0.03 [1] |
Details [5] | |
Mass | 3.09 M☉ |
Radius | 18.37+0.65 −0.88 [1] R☉ |
Luminosity | 184.9±4.6 [1] L☉ |
Surface gravity (log g) | 2.44 cgs |
Temperature | 4966+124 −85 [1] K |
Metallicity [Fe/H] | +0.03 dex |
Rotational velocity (v sin i) | 3.2 km/s |
Age | 331 Myr |
Other designations | |
Database references | |
SIMBAD | data |
Epsilon Sagittae (ε Sagittae) is a solitary, [7] yellow-hued star in the northern constellation of Sagitta. With an apparent visual magnitude of +5.64 to +5.67, [2] it is faintly visible to the naked eye on a dark night. It is a variable star with a small amplitude of 0.03 magnitudes. Based upon an annual parallax shift of 5.60 mas as seen from Earth, [8] it is located roughly 580 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.1 due to interstellar dust. [3]
This is an evolved, G-type giant star with a stellar classification of G8 IIIvar, [3] where the 'var' suffix indicates a variable spectral feature. The star is about 331 million years old with three times the mass of the Sun. [5] It is radiating 185 times the Sun's luminosity from its photosphere at an effective temperature of 4,966 K. [1]
Epsilon Sagittae is an optical binary, with a companion of magnitude 8.35 at an angular separation of 87.3 arc seconds along a position angle of 82°, as of 2013. [9] The companion is actually a more distant giant star approximately 7,000 light-years from Earth, with a luminosity 1,800 times that of the Sun and also designated HD 232029. [10]
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