Program: GS-2019A-Q-125

We are searching for young brown dwarfs at planetary masses (<10 M_Jup) in the Chamaeleon I star-forming region to 1) test star formation theories by constraining the minimum mass of the Initial Mass Function, 2) enable the identification of signatures that can distinguish between planets and brown dwarfs (with JWST), and 3) enable the measurement of the lowest mass at which brown dwarfs harbor the materials for making planets (with JWST). Previously, we have discovered 6 planetary-mass brown dwarfs in Chamaeleon, including the faintest known member (~4 M_Jup, Esplin et al. 2017). To extend our survey to a larger area and lower masses, we have obtained new near-IR images of the cluster with VISTA and Magellan. Combining these data with previously available data (Spitzer, DECam, and Gaia), we have searched for new brown dwarfs in Chamaeleon using optical/IR color-magnitude-diagrams and proper motions. We have identified 9 new candidate brown dwarfs, some of which are fainter (and likely less massive, ~3 M_Jup) than the previously known members of Chamaeleon. We propose to obtain spectra of these candidates with FLAMINGOS-2 to confirm their youth and cool nature.