Epsilon Sextantis

Epsilon Sextantis, Latinized from ε Sextantis, is a solitary,[10] yellow-white hued star in the equatorial constellation of Sextans. With an apparent visual magnitude of 5.24,[2] it is faintly visible to the naked eye on a dark night. The distance to this star, based upon an annual parallax shift of 16.86 mas,[1] is about 193 light years. It is drifting further away from the Sun with a radial velocity of +15 km/s.[4]

ε Sextantis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sextans
Right ascension  10h 17m 37.80200s[1]
Declination −08° 04′ 08.0898″[1]
Apparent magnitude (V) 5.24[2]
Characteristics
Spectral type F0 IV[3]
U−B color index +0.09[2]
B−V color index +0.32[2]
Astrometry
Radial velocity (Rv)+15.2[4] km/s
Proper motion (μ) RA: −160.57[1] mas/yr
Dec.: +2.91[1] mas/yr
Parallax (π)16.86 ± 0.28[1] mas
Distance193 ± 3 ly
(59.3 ± 1.0 pc)
Absolute magnitude (MV)2.42[5]
Details
Mass1.94[6] M☉
Radius3.14+0.18
−0.30[7] R☉
Luminosity23.24±0.55[7] L☉
Surface gravity (log g)3.83±0.08[8] cgs
Temperature7,166±88[8] K
Metallicity [Fe/H]+0.31±0.05[8] dex
Rotational velocity (v sin i)63.5±3.2[5] km/s
Age1.1[6] Gyr
Other designations
ε Sex, 22 Sextantis, BD−07°3001, FK5 1263, HD 89254, HIP 50414, HR 4042, SAO 137469[9]
Database references
SIMBADdata

This is an F-type subgiant star with a stellar classification of F0 IV.[3] However, Malaroda (1975) gave a classification of F2 III,[11] which would indicate a more evolved giant star. It is estimated to have nearly double the mass of the Sun[6] with 3.1[7] times the Sun's radius. The star is around 1.1 billion years old and has a projected rotational velocity of 63.5 km/s.[5] It is radiating 23[7] times the luminosity of the Sun from its photosphere at an effective temperature of 7,166 K.[8]

References
  1. 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.
  2. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", SIMBAD, Bibcode:1986EgUBV........0M.
  3. Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, Ann Arbor, Michigan: Department of Astronomy, University of Michigan, 5, Bibcode:1999MSS...C05....0H.
  4. Wilson, Ralph Elmer (1953), General Catalogue of Stellar Radial Velocities, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
  5. Reiners, A. (January 2006), "Rotation- and temperature-dependence of stellar latitudinal differential rotation", Astronomy and Astrophysics, 446 (1): 267–277, arXiv:astro-ph/0509399, Bibcode:2006A&A...446..267R, doi:10.1051/0004-6361:20053911.
  6. David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146.
  7. 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.
  8. Prugniel, Ph.; et al. (July 2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics, 531: A165, arXiv:1104.4952, Bibcode:2011A&A...531A.165P, doi:10.1051/0004-6361/201116769.
  9. "* eps Sex". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-12-16.
  10. Eggleton, P. P.; et al. (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.
  11. Malaroda, S. (August 1975), "Study of the F-type stars. I. MK spectral types", Astronomical Journal, 80: 637–641, Bibcode:1975AJ.....80..637M, doi:10.1086/111786.
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