Applying a New Polarization-based Diagnostic to an Existing Survey of Classical Be Stars

Type Conference Paper
Names Zachary H. Draper, J. P. Wisniewski, K. Bjorkman, X. Haubois, A. C. Carciofi, J. E. Bjorkman, M. R. Meade
Proceedings Title Bulletin of the American Astronomical Society
Conference Name American Astronomical Society, AAS Meeting #219, #344.19
Volume 219
Date January 1, 2012
URL http://adsabs.harvard.edu/abs/2012AAS...21934419D
Library Catalog NASA ADS
Abstract Classical Be stars are middle-aged, massive B-class stars which rotate rapidly near their critical rate. Through a yet unknown mechanism material is ejected from the star into a circumstellar disk. The density distribution of material within these disks can be diagnosed by studying the polarization signature. A survey of Classical Be stars was conducted by the Pine Bluff Observatory (PBO) using the HPOL instrument from 1989 to 2004, which cataloged optical spectropolarimetry for 75 Be stars. This survey was further supplemented with UV spectropolarimetry from the WUPPE instrument aboard the Astro-1 and Astro-2 Space Shuttle missions. We have developed an IDL-based pipeline to remove interstellar polarization caused by dust along the line of sight to each star for a subset of the survey, thereby allowing us to measure the intrinsic polarization variations due to changes within the disk. We apply a newly-developed diagnostic of the Balmer jump vs V-band polarization to help us better understand the mechanism(s) which causes these stars to form circumstellar disks. We also discuss constraints on axial precession and complex density morphologies.
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