New extinction and mass estimates from optical photometry of the very low mass brown dwarf companion ct Chamaeleontis b with the Magellan AO system

Ya Lin Wu, Laird M Close, Jared R. Males, Travis S Barman, Katie M. Morzinski, Katherine B. Follette, Vanessa Bailey, Timothy J. Rodigas, Philip M Hinz, Alfio Puglisi, Marco Xompero, Runa Briguglio

Research output: Contribution to journalArticle

12 Scopus citations


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.

Original languageEnglish (US)
Article number4
JournalAstrophysical Journal
Issue number1
Publication statusPublished - Mar 1 2015



  • brown dwarfs
  • instrumentation: adaptive optics
  • planetary systems
  • planets and satellites: individual (CT Cha B)
  • stars: individual (CT Cha)
  • stars: pre-main sequence

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

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