Gamma Chamaeleontis

Gamma Chamaeleontis, Latinized from γ Chamaeleontis, is a solitary[9] star located in the southern circumpolar constellation of Chamaeleon. It can faintly be seen with the naked eye on a dark night, having an apparent visual magnitude of 4.12.[2] Based upon an annual parallax shift of 7.81 mas,[1] it is located around 418 light years from the Sun.

γ Chamaeleontis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Chamaeleon
Right ascension  10h 35m 28.10720s[1]
Declination −78° 36′ 28.0321″[1]
Apparent magnitude (V) 4.12[2]
Characteristics
Spectral type K5 III[3]
U−B color index +1.94[2]
B−V color index +1.57[2]
Astrometry
Radial velocity (Rv)−22.4[4] km/s
Proper motion (μ) RA: −37.61[1] mas/yr
Dec.: +11.08[1] mas/yr
Parallax (π)7.81 ± 0.12[1] mas
Distance418 ± 6 ly
(128 ± 2 pc)
Absolute magnitude (MV)−1.43[5]
Details
Radius67[6] R☉
Luminosity864[7] L☉
Temperature4,035[7] K
Other designations
γ Cha, CD−77° 454, FK5 401, HD 92305, HIP 51839, HR 4174, SAO 256731.[8]
Database references
SIMBADdata

This is an evolved K-type giant star with a stellar classification of K5 III.[3] The measured angular diameter, after correction for limb darkening, is 4.86±0.05 mas.[10] At the estimated distance of the star, this yields a physical size of about 67 times the radius of the Sun.[6] It is a suspected variable star, with an amplitude of 0.01 magnitude.[11] The star radiates 864 times the solar luminosity from its outer atmosphere with an effective temperature of 4,053 K.[7]

In the next 7500 years, the south Celestial pole will pass close to this stars (4200 CE).

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 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
  3. Houk, N.; Cowley, A. P. (1975), "Catalogue of two-dimensional spectral types for the HD stars", University of Michigan, I, Bibcode:1975mcts.book.....H.
  4. Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veröff. Astron. Rechen-Inst. Heidelb, Astronomisches Rechen-Institut Heidelberg, 35 (35), Bibcode:1999VeARI..35....1W.
  5. 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.
  6. Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
  7. McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
  8. "gam Cha". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-12-11.
  9. 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  10. Richichi, A.; et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039.
  11. Eggen, O. J. (1973), "The classification of intrinsic variables. IV. Very-small-amplitude, very-short-period red variables", Astrophysical Journal, 184: 793, Bibcode:1973ApJ...184..793E, doi:10.1086/152371.
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