Gamma Mensae

γ Mensae
Location of γ Mensae (circled)
Observation data
Epoch J2000.0      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 mas[6]
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]

  1. ^ a b c Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference Gray2006 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  6. ^ a b c 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.
  7. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Hartkopf2006 was invoked but never defined (see the help page).
  9. ^ a b c Cite error: The named reference Wittenmyer2016 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Foy1980 was invoked but never defined (see the help page).