Dr. Angela Cotera

December 20, 2006

"Imaging Polarimetry of Young Stellar Objects with ACS and NICMOS: A study in dust grain evolution"

HST–GO–10178.6–A

This project is focused on studying the evolution of dust grains around young stellar objects (YSOs) by obtaining NICMOS polarimetry for 10 objects which span the earliest evolutionary stages, and ACS polarimetry for 8 of the same objects. The science objective is to determine the time scale for the growth of grains from the initial small ISM grains to larger grains, the precursors of planetesimals. Since small grains have a much larger fractional polarization and a steeper wavelength dependence than larger grains, observations of the variation of polarized light as a function of wavelength are a sensitive probe for determining the size distribution as a function of evolutionary state.