Authors

Marshall D. Perrin (1), Glenn Schneider (2), Dean Hines (3), and the HST GO 10847, 10852 & 11155 teams

Affiliations

(1) UCLA & STScI; (2) University of Arizona.; (3) Space Sciences Institute & STScI

Abstract

Polarization induced in unpolarized starlight by scattering from circumstellar dust provides a powerful tool for constraining scattering geometry and the nature of the scattering particles. The NICMOS instrument on Hubble offers a unique capability for high contrast, spectrophotometrically calibrated, absolute polarization measurements of circumstellar disks, using the coronagraphic polarimetry mode of its NIC2 camera. Over the past several cycles, we have undertaken a systematic study of dust structures around young stars in three complementary programs, targeting disks around T Tauri and Herbig Ae stars in the early stages of planet formation, plus debris disks around slightly older stars. We summarize the observational results from these programs and present examples of how polarization analyses yield insight into the scattering grain properties.