Epsilon Sagittae
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]
| 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 |
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]
References Edit
- ^ a b c d e f g h i j k 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.
- ^ a b Details for NSV 12213, The International Variable Star Index, 17 December 2005, retrieved 14 September 2018
- ^ a b c 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.
- ^ a b 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.
- ^ a b 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.