NOAO >   Observing Info >   Approved Programs >   2010A-0427

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Proposal Information for 2010A-0427


PI: Kevin R. Covey, Hubble Fellow, Cornell University, kcovey@astro.cornell.edu
Address: Department of Astronomy, 226 Space Sciences Building, Ithaca, NY 14853, USA

CoI: John Stauffer, Spitzer Science Center
CoI: Elaine Winston, University of Exeter
CoI: Rob Gutermuth, Smith College
CoI: Peter Plavchan, NASA Exoplanet Science Institute
CoI: Luisa Rebull, Spitzer Science Center
CoI: Maria Morales Calderon, Spitzer Science Center
CoI: Barbara Whitney, Space Sciences Institute

Title: Testing Models of YSO Disk Heating via Accretion Shocks

Abstract: We propose to obtain multi-object NIR spectroscopy for 100+ Class I and II young-stellar objects (YSOs) targeted by our 550 hour `YSOVAR' Spitzer Warm Mission Exploration Science Program. YSOVAR will obtain >100 epochs of mid-IR photometry for hundreds of YSOs in 11 nearby clusters; our precursor experiments show that roughly half of all YSOs are variable in the mid-IR, and more than half of those appear to be periodic. We propose to conduct two spectroscopic campaigns to study the physical mechanism driving this variability. A fast cadence monitoring program with MOIRCS on Subaru will test if accretion sensitive HI emission lines vary in phase with the mid-IR flux, as predicted by models where accretion shocks heat the inner rim of a YSO's circumstellar disk. The second campaign will utilize MOIRCS and FLAMINGOS on the KPNO 4m to conduct spectroscopic censuses of YSOVAR clusters. These surveys will investigate correlations between mid-IR variability and intrinsic stellar properties (mass, age, accretion rate, etc.). By testing physical models of pre-main sequence mass accretion and disk structure, these linked campaigns will advance our understanding of the physical processes governing star and planet formation.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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