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Gamma Sextantis

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γ Sextantis
Location of γ Sextantis (circled in red)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sextans
Right ascension 09h 52m 30.43727s[1]
Declination −08° 06 18.1269[1]
Apparent magnitude (V) 5.05[2] (5.6 + 6.0)[3]
Characteristics
Evolutionary stage main sequence[4]
Spectral type A0/1 V[5] (A1 V + A4 V)[6]
U−B color index +0.06[2]
B−V color index +0.04[2]
Astrometry
Radial velocity (Rv)+12[7] km/s
Proper motion (μ) RA: −57.28[1] mas/yr
Dec.: −49.26[1] mas/yr
Parallax (π)11.75±0.63 mas[1]
Distance280 ± 10 ly
(85 ± 5 pc)
Absolute magnitude (MV)+0.43[8]
Orbit[9]
Period (P)77.61±0.59 yr
Semi-major axis (a)0.380±0.013
Eccentricity (e)0.741±0.019
Inclination (i)143.2±3.4°
Longitude of the node (Ω)198.5±5.2°
Periastron epoch (T)1956.84±0.69
Argument of periastron (ω)
(secondary)
306.2±6.5°
Details
Mass2.60[10] M
Radius3.2[11] R
Luminosity69[4] L
Surface gravity (log g)4.18±0.14[10] cgs
Temperature9,825±334[10] K
Rotational velocity (v sin i)134.6±1.4[12] km/s
Age401[10] Myr
Other designations
γ Sex, 8 Sextantis, BD−07°2909, HD 85558, HIP 48437, HR 3909, SAO 137199.[13]
Database references
SIMBADdata

Gamma Sextantis, Latinized as γ Sextantis, is a binary star[14] system in the equatorial constellation of Sextans. The combined apparent visual magnitude of the system is 5.05,[2] which means it is faintly visible to the naked eye. The annual parallax shift is 11.75 mas,[1] indicating a distance of around 280 light years.

The two components orbit each other with a period of 77.6 years and a high eccentricity of 0.741. The orbital plane is inclined by 143.2° to the line of sight from the Earth.[9] With a visual magnitude of 5.6,[6] the brighter component Gamma Sextantis A is an A-type main sequence star with a stellar classification of A1 V.[6] The fainter companion Gamma Sextantis B has a classification of A4 V[6] with a magnitude of 6.0.[6] Their combined spectrum matches a classification of A0/1 V.[5] Their angular separation 0.4 arcseconds, so observation with a telescope requires a diameter of at least 30 centimeters.[citation needed]

There is a magnitude 12.28 companion star Gamma Sextantis C at an angular separation of 36.9 arc seconds along a position angle of 333°, as of 2000. This separation has increased from 30.0 arc seconds in 1834. The proper motion of this star differs from the Gamma Sextantis AB system, having proper motions of −29 mas/yr and +5 mas/yr in right ascension and declination, respectively.[15]

References

[edit]
  1. 1 2 3 4 5 6 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.
  2. 1 2 3 4 Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
  3. Heintz, W. D. (March 1982), "Orbits of 16 visual binaries", Astronomy and Astrophysics Supplement Series, 47: 569–573, Bibcode:1982A&AS...47..569H.
  4. 1 2 Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691.
  5. 1 2 Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, 5, Ann Arbor, Michigan: Department of Astronomy, University of Michigan, Bibcode:1999MSS...C05....0H.
  6. 1 2 3 4 5 Edwards, T. W. (April 1976), "MK classification for visual binary components", Astronomical Journal, 81: 245–249, Bibcode:1976AJ.....81..245E, doi:10.1086/111879.
  7. Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
  8. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  9. 1 2 Tokovinin, Andrei; Mason, Brian D.; Mendez, Rene A.; Costa, Edgardo (July 2024), "Speckle Interferometry at SOAR Telescope in 2023", The Astronomical Journal, 168 (1): 28, Bibcode:2024AJ....168...28T, doi:10.3847/1538-3881/ad4d56, ISSN 0004-6256.
  10. 1 2 3 4 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, S2CID 33401607.
  11. McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017). "Fundamental parameters and infrared excesses of Tycho-Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433.
  12. Díaz, C. G.; et al. (July 2011), "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum", Astronomy & Astrophysics, 531: A143, arXiv:1012.4858, Bibcode:2011A&A...531A.143D, doi:10.1051/0004-6361/201016386, S2CID 119286673.
  13. "gam Sex – Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-12-14.
  14. 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, S2CID 14878976.
  15. 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.