Location of ε Sagittae (circled) | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Sagitta |
| Right ascension | 19 37 17.39324 |
| Declination | +16° 27′ 46.0871″ |
| Apparent magnitude (V) | +5.64 to +5.67 |
| Characteristics | |
| Spectral type | G8 IIIvar |
| U−B color index | +0.83 |
| B−V color index | +1.00 |
| Astrometry | |
| Radial velocity (Rv) | −32.49±0.18 km/s |
| Proper motion (μ) | RA: +16.382±0.164 mas/yr Dec.: +14.364±0.135 mas/yr |
| Parallax (π) | 5.6067 ± 0.1173 mas |
| Distance | 580 ± 10 ly (178 ± 4 pc) |
| Absolute magnitude (MV) | −0.84±0.03 |
| Details | |
| Mass | 3.09 M☉ |
| Radius | 18.37+0.65 −0.88 R☉ |
| Luminosity | 184.9±4.6 L☉ |
| Surface gravity (log g) | 2.44 cgs |
| Temperature | 4966+124 −85 K |
| Metallicity | +0.03 dex |
| Rotational velocity (v sin i) | 3.2 km/s |
| Age | 331 Myr |
| Other designations | |
| ε Sge, 4 Sge, BD+16°3918, HD 185194, HIP 96516, HR 7463, WDS J19373+1628A | |
| Database references | |
| SIMBAD | data |
Epsilon Sagittae (ε Sagittae) is a solitary, yellow-hued star in the northern constellation of Sagitta. With an apparent visual magnitude of +5.64 to +5.67, 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, 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.
This is an evolved, G-type giant star with a stellar classification of G8 IIIvar, 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. It is radiating 185 times the Sun's luminosity from its photosphere at an effective temperature of 4,966 K.
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. 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.
References
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ Details for NSV 12213, The International Variable Star Index, 17 December 2005, retrieved 14 September 2018
- ^ Takeda, Yoichi; et al. (August 2008), "Stellar Parameters and Elemental Abundances of Late-G Giants", Publications of the Astronomical Society of Japan, 60 (4): 781–802, arXiv:0805.2434, Bibcode:2008PASJ...60..781T, doi:10.1093/pasj/60.4.781.
- ^ Argue, A. N. (1966), "UBV photometry of 550 F, G and K type stars", Monthly Notices of the Royal Astronomical Society, 133 (4): 475–493, Bibcode:1966MNRAS.133..475A, doi:10.1093/mnras/133.4.475.
- ^ Takeda, Yoichi; Tajitsu, Akito (2014), "Spectroscopic study on the beryllium abundances of red giant stars", Publications of the Astronomical Society of Japan, 66 (5): 91, arXiv:1406.7066, Bibcode:2014PASJ...66...91T, doi:10.1093/pasj/psu066.
- "eps Sge". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-14.
{{cite web}}: CS1 maint: postscript (link) - Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
- Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
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