CT Chamaeleontis

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CT Chamaeleontis
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Chamaeleon
Right ascension  11h 04m 09.0989s[1]
Declination −76° 27′ 19.3269″[1]
Apparent magnitude (V) 12.31 to 12.43[2]
Spectral type K7[3]
B−V color index −0.9[3]
V−R color index 0.8[3]
Variable type INB[2]
Radial velocity (Rv)15.1 ± 0.5[3] km/s
Proper motion (μ) RA: −22.209±0.039[1] mas/yr
Dec.: −0.175±0.035[1] mas/yr
Parallax (π)5.2144 ± 0.0211[1] mas
Distance625 ± 3 ly
(191.8 ± 0.8 pc)
Other designations
CT Cha, 2MASS J11040909-7627193, IRAS 11027-7611, NSV 5081, WDS J11042-7627AB
Database references

CT Chamaeleontis b
Exoplanet Comparison CT Chamaeleontis b.png
A size comparison between the colossal planet CT Chamaeleontis b and Jupiter.
Position (relative to CT Chamaleontis)
Epoch of observation2006–2007
Angular distance2.670 [4]
Position angle300.7° [4]
Observed separation
~440 AU [4]
Spectral type M8–L0[4]
Mass17 ± 6 MJup
Luminosity0.002 L
Surface gravity (log g)3.5 cgs
Temperature2,600 ± 250 K
Other designations
CT Cha b.
Database references

CT Chamaeleontis (CT Cha) is a T Tauri star in the constellation of Chamaeleon.[3] It has an apparent visual magnitude which varies between 12.31 and 12.43.[2]

In 2006 and 2007, a faint companion was observed 2.7 arcseconds away from CT Chamaeleontis, using the Very Large Telescope at the European Southern Observatory. Since the object shares common proper motion with CT Chamaleontis, it is believed to be physically close to the star, with a projected separation of approximately 440 astronomical units. It is estimated to have a mass of approximately 17 Jupiter masses and is probably a brown dwarf or a planet.[4] The companion has been designated CT Chamaeleontis b.[5]

The CT Chamaeleontis system
Companion MassObserved separation
Discovery year
b17 ± 6 MJ2002008


  1. ^ a b c d e 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. Gaia DR2 record for this source at VizieR.
  2. ^ a b c CT Cha, database entry, The combined table of GCVS Vols I-III and NL 67-78 with improved coordinates, General Catalogue of Variable Stars, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line October 1, 2008.
  3. ^ a b c d e V* CT Cha -- T Tau-type Star, database entry, SIMBAD. Accessed on line October 1, 2008.
  4. ^ a b c d e f g Direct evidence of a sub-stellar companion around CT Cha, T. O. B. Schmidt et al., accepted for publication in Astronomy and Astrophysics, Bibcode2008arXiv0809.2812S, arXiv:0809.2812.
  5. ^ NAME CT Cha b -- Extra-solar Planet Candidate, database entry, SIMBAD. Accessed on line October 1, 2008.