New Extinction and Mass Estimates from Optical Photometry of the Very Low Mass Brown Dwarf Companion CT Chamaeleontis B with the Magellan AO System
Journal
Date Issued
2015
Author(s)
Wu, Ya-Lin
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Close, Laird M.
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Males, Jared R.
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Barman, Travis S.
•
Morzinski, Katie M.
•
Follette, Katherine B.
•
Bailey, Vanessa
•
Rodigas, Timothy J.
•
Hinz, Philip
•
•
•
Description
We thank the anonymous referee for helpful comments that greatly improved this manuscript. We thank Professor Jennifer Patience for kindly providing the SINFONI spectra of CT Cha B. We thank the whole Magellan Staff for making this wonderful telescope possible. We would especially like to thank Povilas Palunas (for help over the entire MagAO commissioning run). Juan Gallardo, Patricio Jones, Emilio Cerda, Felipe Sanchez, Gabriel Martin, Maurico Navarrete, Jorge Bravo and the whole team of technical experts helped do many exacting tasks in a very professional manner. Glenn Eychaner, David Osip and Frank Perez all gave expert support which was fantastic. It is a privilege to be able to commission an AO system on such a fine telescope and site. The MagAO system was developed with support from the NSF MRI and TSIP programs. The VisAO camera was developed with help from the NSF ATI program. Y.L.W.'s and L.M.C.'s research was supported by NSF AAG and NASA Origins of Solar Systems grants. J.R.M. is grateful for the generous support of the Phoenix ARCS Foundation. J.R.M. and K.M. were supported under contract with the California Institute of Technology funded by NASA through the Sagan Fellowship Program.
Abstract
We used the Magellan adaptive optics system and its VisAO CCD camera to image the young low mass brown dwarf companion CT Chamaeleontis B for the first time at visible wavelengths. We detect it at r', i', z', and YS . With our new photometry and T eff ~ 2500 K derived from the shape of its K-band spectrum, we find that CT Cha B has AV = 3.4 ± 1.1 mag, and a mass of 14-24 MJ according to the DUSTY evolutionary tracks and its 1-5 Myr age. The overluminosity of our r' detection indicates that the companion has significant Hα emission and a mass accretion rate ~6 × 10-10 M ☉ yr-1, similar to some substellar companions. Proper motion analysis shows that another point source within 2'' of CT Cha A is not physical. This paper demonstrates how visible wavelength adaptive optics photometry (r', i', z', YS ) allows for a better estimate of extinction, luminosity, and mass accretion rate of young substellar companions.
This paper includes data gathered with the 6.5 m Magellan Clay Telescope at Las Campanas Observatory, Chile.
Volume
801
Issue
1
Start page
4
Issn Identifier
0004-637X
Ads BibCode
2015ApJ...801....4W
Rights
open.access
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