Gamma Chamaeleontis

γ Chamaeleontis

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Chamaeleon
Right ascension	10^h 35^m 28.10720^s[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 mas[1]
Distance	418 ± 6 ly (128 ± 2 pc)
Absolute magnitude (MV)	−1.43[5]
Details
Radius	67[6] R☉
Luminosity	864[7] L☉
Temperature	4,035[7] K
Other designations
γ Cha, CD−77° 454, FK5 401, HD 92305, HIP 51839, HR 4174, SAO 256731.[8]
Database references
SIMBAD	data

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.

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]

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, S2CID 18759600.
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 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.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, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, 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, S2CID 119257644.
6. Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R_*) is given by:

   ${\displaystyle {\begin{aligned}2\cdot R_{*}&={\frac {(128\cdot 4.86\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 133.8\cdot R_{\bigodot }\end{aligned}}}$

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, S2CID 118665352.
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, S2CID 14878976.
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.