Astronomy:Epsilon Sagittae
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| Observation data 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[1] mas |
| 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 | |
| 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
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 Details for NSV 12213, The International Variable Star Index, 17 December 2005, https://www.aavso.org/vsx/index.php?view=detail.top&oid=50837, retrieved 14 September 2018
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Reffert, Sabine; Bergmann, Christoph; Quirrenbach, Andreas; Trifonov, Trifon; Künstler, Andreas (2015), "Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity", Astronomy and Astrophysics 574: A116, doi:10.1051/0004-6361/201322360, Bibcode: 2015A&A...574A.116R.
- ↑ 4.0 4.1 4.2 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, doi:10.1093/pasj/60.4.781, Bibcode: 2008PASJ...60..781T.
- ↑ 5.0 5.1 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, doi:10.1093/mnras/133.4.475, Bibcode: 1966MNRAS.133..475A.
- ↑ 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, doi:10.1093/pasj/psu066, Bibcode: 2014PASJ...66...91T.
- ↑ "eps Sge". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=eps+Sge.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M.
- ↑ Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
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