Wikipedia

CT Chamaeleontis

CT Chamaeleontis (CT Cha) is a T Tauri star - a primary of the star system in the constellation of Chamaeleon.[8] 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.[7]

CT Chamaeleontis

CT Chamaeleontis and its companion (faint object on the upper right near the star)
Credit: NASA/ESA/CSA JWST; Ya-Lin Wu et al.; processing: Meli_thev
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 Ve[3]
Variable type INB[2]
B
Spectral type M8–L0[4]
Astrometry
Radial velocity (Rv)15.13±0.09[5] 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 mas[1]
Distance625 ± 3 ly
(191.8 ± 0.8 pc)
Position (relative to CT Chamaeleontis)
ComponentB
Epoch of observation2006–2007
Angular distance2.670″ [4]
Position angle300.7° [4]
Projected separation~440 AU [4]
Details[4][6]
A
Mass0.796+0.015
−0.014 M☉
Radius2.06±0.05 R☉
Luminosity1.41+0.17
−0.16 L☉
Surface gravity (log g)4.5+0.7
−1.2 cgs
Temperature4,402+151
−166 K
Age2±2[4] Myr
B
Mass19±5[7] MJup
Radius2.20+0.81
−0.60 RJup
Luminosity0.002 L☉
Surface gravity (log g)3.5 cgs
Temperature2,500±100[7] K
Age2±2[4] Myr
Other designations
CT Cha, 2MASS J11040909-7627193, IRAS 11027-7611, NSV 5081, WDS J11042-7627AB
Database references
SIMBADdata
B

Cuno Hoffmeister discovered that CT Chamaeleontis is a variable star in 1962.[9] It was given its variable star designation in 1981.[10]

Brown dwarf/Planetary system

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A visual band light curve for CT Chamaeleontis, plotted from ASAS data[11]

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 either designated as CT Chamaeleontis b[12] or as CT Chamaeleontis B, sometimes erroneously as low-mass star.[13] The companion was proven to be most likely in the brown dwarf mass range in 2015.[7]

The CT Chamaeleontis planetary system[6][14][7][4]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
protoplanetary disk[6] 6.1–9.3 AU 54.0+1.0
−0.9° 		—
protoplanetary disk[14] 64.6±4.2 AU 45.7±5.0° —
B 19±5[7] MJ 514 — — — 2.20+0.81
−0.60[4] RJ

References

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  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 Archived 2017-06-20 at the Wayback Machine, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line October 1, 2008.
  3. ^ Torres, C. A. O.; Quast, G. R.; da Silva, L.; de la Reza, R.; Melo, C. H. F.; Sterzik, M. (12 September 2006). "Search for associations containing young stars (SACY)". Astronomy & Astrophysics. 460 (3): 695–708. arXiv:astro-ph/0609258. Bibcode:2006A&A...460..695T. doi:10.1051/0004-6361:20065602. eISSN 1432-0746. ISSN 0004-6361.
  4. ^ a b c d e f g h i j 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. ^ Nguyen, Duy Cuong; Brandeker, Alexis; van Kerkwijk, Marten H.; Jayawardhana, Ray (6 January 2012). "Close Companions to Young Stars. I. A Large Spectroscopic Survey in Chamaeleon I and Taurus-Auriga". The Astrophysical Journal. 745 (2): 119. arXiv:1112.0002. Bibcode:2012ApJ...745..119N. doi:10.1088/0004-637X/745/2/119. eISSN 1538-4357. ISSN 0004-637X.
  6. ^ a b c 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.
  7. ^ a b c d e f 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.
  8. ^ V* CT Cha -- T Tau-type Star, database entry, SIMBAD. Accessed on line October 1, 2008.
  9. ^ Hoffmeister, C. (1962). "Ein System von Dunkelwolken bei ɛ Chamaeleonits. Mit 4 Textabbildungen". Zeitschrift für Astrophysik. 55: 290. Bibcode:1962ZA.....55..290H. Retrieved 8 October 2024.
  10. ^ Kholopov, P. N.; Samus, N. N.; Kukarkina, N. P.; Medvedeva, G. I.; Perova, N. B. (February 1981). "65th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 1921. Bibcode:1981IBVS.1921....1K. Retrieved 8 October 2024.
  11. ^ "ASAS All Star Catalogue". The All Sky Automated Survey. Retrieved 8 December 2021.
  12. ^ "Planet CT Cha b". Encyclopaedia of exoplanetary systems / Exoplanet.eu. Retrieved 2024-08-20.
  13. ^ NAME CT Cha B -- Extra-solar Planet Candidate, database entry, SIMBAD. Accessed on line October 1, 2008.
  14. ^ a b Ginski, C.; Garufi, A.; Benisty, M.; Tazaki, R.; Dominik, C.; Ribas, á.; Engler, N.; Birnstiel, T.; Chauvin, G.; Columba, G.; Facchini, S.; Goncharov, A.; Hagelberg, J.; Henning, T.; Hogerheijde, M.; van Holstein, R. G.; Huang, J.; Muto, T.; Pinilla, P.; Kanagawa, K.; Kim, S.; Kurtovic, N.; Langlois, M.; Manara, C.; Milli, J.; Momose, M.; Orihara, R.; Pawellek, N.; Pinte, C.; Rab, C.; Schmidt, T. O. B.; Snik, F.; Wahhaj, Z.; Williams, J.; Zurlo, A. (May 2024). "The SPHERE view of the Chamaeleon I star-forming region: The full census of planet-forming disks with GTO and DESTINYS programs". Astronomy & Astrophysics. 685: A52. arXiv:2403.02149. Bibcode:2024A&A...685A..52G. doi:10.1051/0004-6361/202244005.
 

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