Epsilon Sagittae
Location of ε Sagittae (circled) | |
| 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 | |
| Evolutionary stage | horizontal branch[3] |
| Spectral type | G8 IIIvar[4] |
| U−B color index | +0.83[5] |
| B−V color index | +1.00[5] |
| 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 | |
| Mass | 2.9[3] M☉ |
| Radius | 18.37+0.65 −0.88[1] R☉ |
| Luminosity | 184.9±4.6[1] L☉ |
| Surface gravity (log g) | 2.52[3] cgs |
| Temperature | 4966+124 −85[1] K |
| Metallicity [Fe/H] | +0.02[3] dex |
| Rotational velocity (v sin i) | 3.2[6] km/s |
| Age | 520[3] Myr |
| Other designations | |
| ε Sge, 4 Sge, BD+16°3918, HD 185194, HIP 96516, HR 7463, WDS J19373+1628A[7] | |
| Database references | |
| SIMBAD | data |
Epsilon Sagittae (ε Sagittae) is a solitary,[8] 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,[9] 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.[4]
This is an evolved, G-type giant star with a stellar classification of G8 IIIvar,[4] where the 'var' suffix indicates a variable spectral feature. The star is about 520 million years old with about three times the mass of the Sun.[3] 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.[10] 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.[11]
References
[edit | edit source]- ^ a b c d e f g h i j k Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR2 record for this source at VizieR.
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c d e f Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR2 record for this source at VizieR.
