Astronomy:Gamma Mensae

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Short description: Astrometric binary star system in the constellation Mensa
γ Mensae
Mensa IAU.svg
Red circle.svg
Location of γ Mensae (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Mensa
Right ascension  05h 31m 53.01393s[1]
Declination −76° 20′ 27.4779″[1]
Apparent magnitude (V) 5.19[2]
Characteristics
Spectral type K2 III[3][4]
U−B color index +1.18[2]
B−V color index +1.13[2]
Astrometry
Radial velocity (Rv)+56.7±0.8[5] km/s
Proper motion (μ) RA: +140.646[6] mas/yr
Dec.: +269.634[6] mas/yr
Parallax (π)31.1021 ± 0.1519[6] mas
Distance104.9 ± 0.5 ly
(32.2 ± 0.2 pc)
Absolute magnitude (MV)+2.70[7]
Orbit[8]
Period (P)7.455±4.857 yr
Semi-major axis (a)51±10
Eccentricity (e)0.59±0.15
Inclination (i)53±8°
Longitude of the node (Ω)117±90°
Periastron epoch (T)1995.111±4.085
Argument of periastron (ω)
(secondary)
124±74°
Details[9]
γ Men A
Mass1.04 M
Radius4.99 R
Luminosity21 L
Surface gravity (log g)2.76[3] cgs
Temperature4,491[3] K
Metallicity [Fe/H]+0.22 dex
Age10.60 Gyr
Other designations
γ Men, CD−76° 222, HD 37763, HIP 25918, HR 1953, SAO 256201[10]
Database references
SIMBADdata

Gamma Mensae, Latinized from γ Mensae, is an orange-hued star system in the southern constellation of Mensa. The apparent visual magnitude of 5.19[2] indicates it is dimly visible to the naked eye. Based upon an annual parallax shift of 7.70 mas as seen from the Earth,[1] it is about 102 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.033 due to interstellar dust.[9] The system shows the high velocity kinematic properties of a population II star, but has Sun-like abundances of most elements.[11]

This is a probable astrometric binary system[4] with poorly constrained orbital elements. The visible member, component A, is an evolved K-type giant star with a stellar classification K2 III[3] At about 10.6 billion years of age, it has nearly the same mass as the Sun but has expanded to five times the Sun's radius.[9] The star shines with 21 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,491 K.[3]

References

  1. 1.0 1.1 1.2 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 2.3 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode1966CoLPL...4...99J. 
  3. 3.0 3.1 3.2 3.3 3.4 Gray, R. O. et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal 132 (1): 161–170, doi:10.1086/504637, Bibcode2006AJ....132..161G. 
  4. 4.0 4.1 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, Bibcode2008MNRAS.389..869E. 
  5. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics 546: 14, doi:10.1051/0004-6361/201219219, A61, Bibcode2012A&A...546A..61D. 
  6. 6.0 6.1 6.2 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. Bibcode2018A&A...616A...1G. 
  7. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  8. Hartkopf, W. I. et al. (June 30, 2006), Sixth Catalog of Orbits of Visual Binary Stars, United States Naval Observatory, http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6, retrieved 2017-06-02. 
  9. 9.0 9.1 9.2 Wittenmyer, Robert A.; Liu, Fan; Wang, Liang; Casagrande, Luca; Johnson, John Asher; Tinney, C. G. (July 2016), "The Pan-Pacific Planet Search. V. Fundamental Parameters for 164 Evolved Stars", The Astronomical Journal 152 (1): 15, doi:10.3847/0004-6256/152/1/19, 19, Bibcode2016AJ....152...19W. 
  10. "gam Men". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=gam+Men. 
  11. Foy, R. (May 1980), "Detailed analysis of high velocity stars", Astronomy and Astrophysics 85 (3): 287–294, Bibcode1980A&A....85..287F.