Spitzer Space Telescope - Archive Research Proposal #40857


A Wide-Field Low-Mass Census of the Nearest Star-Forming Region

Principal Investigator: Michael Liu
           Institution: University of Hawaii

     Technical Contact: Michael Liu, University of Hawaii

Co-Investigators: 
Katelyn Allers, IfA/Hawaii                                            
Eugene Magnier, IfA/Hawaii                                            

Science Category: star formation 
Dollars Approved: 76632 

Abstract:
We propose to conduct a very wide-field census of young low-mass stars and brown
dwarfs across the rho Ophiuchus cloud complex. Through a combination of archival
c2d Spitzer Legacy data, the 2MASS all-sky catalog, and our own optical
proper-motion imaging program, we will survey an area of 5 square degrees for
young objects possessing circumstellar disks down to ~15 Mjup. Our selection
methods have been proven to be exceptionally efficient, almost entirely free of
the false positives (e.g. reddened background sources) that plague previous
searches. Our census will represent more than an order of magnitude increase in
area compared to past studies of this region and is uniquely capability of
identifying the dispersed young population. For the resulting census of low-mass
stars and brown dwarfs, we will examine (1) the spatial distribution, (2) the
disk structural properties (flat versus flared), and (3) the kinematic
properties. Our proposed study will allow, for the first time, an examination of
low-mass disk properties over a range of host star mass, ages, local density,
and extinction within a single star-forming cloud complex. Moreover, in light of
the current active emphasis to push to the lowest possible substellar masses
with deep pencil beam surveys, our proposed study will provide complementary
insights into the star/brown dwarf formation process over a very large spatial
scales (~10 pc). Finally, the resulting populous census of young low-mass
objects will provide a rich sample for detailed follow-up with current and
future telescopes.