Spitzer Space Telescope - General Observer Proposal #60169


Search for Pulsation in Young Brown Dwarfs

Principal Investigator: Ann Marie Cody
           Institution: California Institute of Technology

     Technical Contact: Ann Marie Cody, California Institute of Technology

Co-Investigators: 
Lynne Hillenbrand, California Institute of Technology                 

Science Category: brown dwarfs/very low mass stars 
 Observing Modes: IRAC Post-Cryo Mapping
  Hours Approved: 24.0 

Abstract:
Brown dwarfs are a ubiquitous yet poorly understood product of the processes
that take place in star formation regions. To date, observational methods to
determine important properties such as mass and age are lacking. But better
understanding of the physical characteristics of young brown dwarfs and very low
mass stars is now within reach through the signature of variable lightcurves.
In particular, pulsation in these objects is a newly suggested phenomenon that
offers unprecedented opportunities to probe their interiors and evolution. We
propose to use Spitzer IRAC to improve upon ground-based studies which suggest
low-amplitude, short-period variability indicative of pulsation just below the
statistical detection threshold. We will acquire precise time-series photometry
on a sample of confirmed brown dwarfs in the young Sigma Orionis cluster. With
estimated masses and ages appropriate to the deuterium-burning stage, these
objects are some of the most promising candidates in a potential new class of
pulsators. We aim to fully characterize light-curve periodicities down to
millimagnitude amplitudes, and ultimately use the results to provide fundamental
constraints on the interiors and properties of brown dwarfs.