PI: Frederick M Walter, Stony Brook University, firstname.lastname@example.org
Address: Dept of Physics & Astronomy, Stony Brook, NY 11794-3800, USA
CoI: Jacqueline Faherty, Carnegie Institution of Washington
Title: Spectral Energy Distributions of 2 Million Year Old Substellar Mass Objects in Orion OB1b
Abstract: OB associations are ideal sites for probing the formation of low mass objects. We are engaged in a systematic study of the very lowest mass objects in Orion OB1, the largest nearby OB association. We have completed a wide-field near-IR (JHK) survey of ~18 sq deg in the Orion OB1a and OB1b associations using the CPAPIR camera on the SMARTS/CTIO 1.5m telescope. This survey reaches to K~17, with a completness limit about 1.5 mag deeper than the 2MASS catalog. Based on J-K colors, we have identified thousands of substellar mass candidates. At a 2 million year age the substellar mass objects have M6- M7 spectral types. J-K is a poor temperature discriminant among the M- type spectra, so there is significant foreground contamination from early M dwarfs. We propose to use DECam to obtain grizY images of this region. The grizYJHK spectral energy distributions will clearly reveal the low mass population of the OB association. The spatially- resolved mass function will give heretofore unavailable insights into how the substellar mass objects form, and whether their final masses are a consequence of proximity to massive stars.
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