AAS 205th Meeting, 9-13 January 2005
Session 109 Surveys for Young Stars Down to the Brown Dwarf Limit
Poster, Wednesday, January 12, 2005, 9:20am-6:30pm, Exhibit Hall

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[109.08] The Sub-stellar Population of Chamaeleon II

K.N. Allers, DT Jaffe (UT Austin), F Allard, I Baraffe (CRAL), N.S. van der Bliek (NOAO/CTIO)

We present preliminary results of a deep near-infrared survey toward Chamaeleon II, a star formation region being observed in the mid-infrared as part of the Spitzer Legacy Program: "From Molecular Cores to Planet Forming Disks". A deep 1-10 micron survey is the key to identifying candidate young, Jupiter-mass objects. The limits of our survey (24.5, 20, 19, and 18 in I, J, H & Ks) combined with the Spitzer IRAC limits permit us to detect young (t < 10 Myr) objects down to 2 Jupiter masses. The availability of photometry over the whole range where these objects emit will make it possible to more accurately distinguish cloud members from background stars than has been possible to date when only near-IR data were available. Our objects provide a testbed for validating atmospheric and evolutionary models of massive planets in a context where light from a parent star does not overwhelm the emission of the substellar object. For objects in the broad gap between the 2MASS limits and out limits, our data provide information about the photospheres. By looking for excess emission in the mid-IR, we detect circumstellar disks around brown dwarfs. For the subset of objects in our fields with disks, we constrain the IMF to masses below the deuterium burning limit. We will use the Spitzer results in combination with current disk models to learn about the presence and nature of cicumstellar disks around young brown dwarfs.

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© 2004. The American Astronomical Society.