%0 Journal Article
%T New Extinction and Mass Estimates from Optical Photometry of the Very Low Mass Brown Dwarf Companion CT Chamaeleontis B with the Magellan AO System
%A Ya-Lin Wu
%A Laird M. Close
%A Jared R. Males
%A Travis S. Barman
%A Katie M. Morzinski
%A Katherine B. Follette
%A Vanessa Bailey
%A Timothy J. Rodigas
%A Philip Hinz
%A Alfio Puglisi
%A Marco Xompero
%A Runa Briguglio
%J Physics
%D 2015
%I arXiv
%R 10.1088/0004-637X/801/1/4
%X We used the Magellan adaptive optics (MagAO) 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 Teff~2500 K derived from the shape 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 Halpha emission and a mass accretion rate ~6*10^-10 Msun/yr, 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 AO photometry (r', i', z', Ys) allows for a better estimate of extinction, luminosity, and mass accretion rate of young substellar companions.
%U http://arxiv.org/abs/1501.01396v1