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Session 57 - Astrophysical Diagnostics from Polarimetry.
Display session, Wednesday, June 12
We investigate the geometry of several classical Be stars using spectropolarimetric data from Pine Bluff Observatory (PBO) and the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE) and a three-dimensional Monte Carlo radiative transfer code which simulates the multiple scatterings of photons. The Be stars we model here each have a different spectral class and v \sin i and our results indicate a general pattern for the geometry of Be stars. By matching the observed spectropolarimetric data of the Be stars \psi Per, \phi Per and \gamma Cas using the technique developed by Wood et al (1996), we can constrain the density and opening angle of the circumstellar disk. We find that the opening angle of the circumstellar disk must be only a few degrees, thus supporting the Wind-Compressed Disk model of Be stars. Although we are also able to find a thick disk solution, we believe it can be ruled out by optical interferometry. Another possible discriminant is that the thin disk solution predicts a 90 degree position angle flip in the IR which does not occur in the thick disk solution. Our results depict the broad applicability of this radiative transfer code and we look forward to using this technique on all of the Oe/Be stars observed by WUPPE.
This research has been supported under NASA contract NAS-26777 and NASA grants NAGW-2921 and NAGW-4527 to the University of Wisconsin. MEP also acknowledges support from a scholarship from The University League.
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