CT Chamaeleontis

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]

CT Chamaeleontis

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]
Characteristics
A
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]
B
Spectral type	M8–L0[4]
Astrometry
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
Distance	625 ± 3 ly (191.8 ± 0.8 pc)
Position (relative to CT Chamaeleontis)
Component	B
Epoch of observation	2006–2007
Angular distance	2.670″ [4]
Position angle	300.7° [4]
Observed separation (projected)	~440 AU [4]
Details[4][5]
A
Mass	0.796+0.015 −0.014 M☉
Radius	2.06±0.05 R☉
Luminosity	1.41+0.17 −0.16 L☉
Surface gravity (log g)	4.5+0.7 −1.2 cgs
Temperature	4,402+151 −166 K
Age	4 Myr
B
Mass	19±5[6] MJup
Radius	2.2+0.81 −0.6 RJup
Luminosity	0.002 L☉
Surface gravity (log g)	3.5 cgs
Temperature	2,500±100[6] K
Age	4 Myr
Other designations
CT Cha, 2MASS J11040909-7627193, IRAS 11027-7611, NSV 5081, WDS J11042-7627AB
Database references
SIMBAD	data
	B

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]