CT Chamaeleontis

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CT Chamaeleontis
Exoplanet Comparison CT Chamaeleontis b.png
A size comparison between the brown dwarf CT Chamaeleontis B and Jupiter
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]
Evolutionary stage T Tauri star
Spectral type K7[3]
B−V color index −0.9[3]
V−R color index 0.8[3]
Variable type INB[2]
Spectral type M8–L0[4]
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)
Position (relative to CT Chamaeleontis)
Epoch of observation2006–2007
Angular distance2.670 [4]
Position angle300.7° [4]
Observed separation
~440 AU [4]
Radius2.06±0.05 R
Surface gravity (log g)4.5+0.7
Mass19±5[6] MJup
Luminosity0.002 L
Surface gravity (log g)3.5 cgs
Temperature2,500±100[6] K
Other designations
CT Cha, 2MASS J11040909-7627193, IRAS 11027-7611, NSV 5081, WDS J11042-7627AB
Database references

CT Chamaeleontis (CT Cha) is a T Tauri star - a primary of the star system in the constellation of Chamaeleon.[3] It has an apparent visual magnitude which varies between 12.31 and 12.43.[2] The star is still accreting material at rate 6×10−10 M/year.[6]

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 Chamaeleontis, 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.[7] The companion was proven to be in the brown dwarf mass range in 2015.[6]

The CT Chamaeleontis planetary system[5]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
debris disk 6.1–9.3 AU 54.0+1.0
B 19±5 MJ 514


  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 Schmidt, T. O. B.; Neuhäuser, R.; Seifahrt, A.; Vogt, N.; Bedalov, A.; Helling, Ch.; Witte, S.; Hauschildt, P. H. (2008). "Direct evidence of a sub-stellar companion around CT Chamaeleontis". Astronomy & Astrophysics. 491 (1): 311–320. arXiv:0809.2812. Bibcode:2008A&A...491..311S. doi:10.1051/0004-6361:20078840. S2CID 17161561.
  5. ^ a b Sheehan, Patrick D.; Wu, Ya-Lin; Eisner, Josh A.; Tobin, John J. (2019). "High Precision Dynamical Masses of Pre-Main Sequence Stars with ALMA and Gaia". The Astrophysical Journal. 874 (2): 136. arXiv:1903.00032. Bibcode:2019ApJ...874..136S. doi:10.3847/1538-4357/ab09f9. S2CID 119218828.
  6. ^ a b c d Wu, Ya-Lin; Close, Laird M.; Males, Jared R.; Barman, Travis S.; Morzinski, Katie M.; Follette, Katherine B.; Bailey, Vanessa; Rodigas, Timothy J.; Hinz, Philip; Puglisi, Alfio; Xompero, Marco; Briguglio, Runa (2015). "New Extinction and Mass Estimates from Optical Photometry of the Very Low Mass Brown Dwarf Companion CT Chamaeleontis B with the Magellan AO System". The Astrophysical Journal. 801 (1): 4. arXiv:1501.01396. Bibcode:2015ApJ...801....4W. doi:10.1088/0004-637X/801/1/4. S2CID 96467798.
  7. ^ NAME CT Cha B -- Extra-solar Planet Candidate, database entry, SIMBAD. Accessed on line October 1, 2008.