A High Dynamic Range Polarimetric Survey of Circumstellar Disks with Adaptive Optics

University Of Arizona, Tucson AZ

Investigators

Abstract

AST 0206351 PI Close Currently, the bulk of our understanding of dust in circumstellar disks comes indirectly through unresolved observations (i.e. observations that spatially confuse light from the disk and the star) where there is little or no information as to the morphological and physical processes that the disks are undergoing. The high contrast between the central starlight and the light scattered from the disk poses a difficult technical challenge, and, until now, this has prevented the efficient resolved detection of large numbers of disks. The investigators will take advantage of a novel high-dynamic range imaging technique (Adaptive Optics aided Wollaston polarimetry), highly sensitive to the polarized light scattered from a disk (eliminating the contaminating unpolarized thermal emission from the star), developed by the group, to create a database of 60 high angular resolution, high sensitivity polarimetric observations of circumstellar disks around young stars from a variety of nearby star forming regions equally sampled over the age range of 100,000 -100,000,000 years. This data will be expertly analyzed with help from the experienced and knowledgeable star formation group at the University of Arizona to extract physical disk parameters from the polarimetric data, such as the disk inclination, scale height, radial extent, density estimates, and dust size distribution. With this new wealth of information, questions regarding the relationship between circumstellar disks and their environment, for example the parent star mass, the effects of a companion star, and the initial conditions for planetary formation, may be answered. This project also includes the commissioning of a dual imaging polarimeter in the new University of Arizona near-infrared camera, to work in tandem with the adoptive optics system currently being developed for the 6.5 meter telescope on Mount Hopkins. ***