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Date: Thu, 16 Dec 93 10:00:12 CST From: rab@simplicio.as.utexas.edu (Bob Benjamin) Subject: Spectropolarimetry of Nova Cas 1993 Hi everyone, The following has been submitted as an IAU circular. Thought some of you might be interested in it. NOVA CASSIOPEIAE 1993 S.R. Trammell and R.A. Benjamin, University of Texas, report: "Optical spectropolarimetry (range 450-720 nm; dispersion 0.269 nm/pixel) obtained with the 2.7m telescope at McDonald Observatory on Dec 14.06 UT, shows a high continuum polarization of 1.84+-0.05 % at position angle 61+-1. There is a 0.4% drop in polarization across H-alpha with a 10+-2 degree position angle rotation, which indicates some polarization is intrinsic to the nova, and suggests an asymmetric geometry." There is some more to this story, but we couldn't afford to tell it in an IAU Circular. We measure the H-alpha polarization, after continuum subtraction, to be P=1.47%+-0.1 at a postion angle of 51+-2 degrees. We have also estimated the interstellar polarization in the direction of the nova (using published polarization measurements of nearby stars) to be P=1.5 +- 0.4% at a postion angle of 55+-10 degrees. The H-alpha polarization is consistent with this value, suggesting that the H-alpha polarization may be interstellar in origin while the continuum polarization is intrinsic to the nova. There is a less pronounced dip in the polarization and a rotation of the postion angle at H-beta. Interested people should contact Susan (srt@astro.as.utexas.edu) or Bob (rab@astro.as.utexas.edu). Both of us will be travelling a fair amount over the next three weeks though, so don't depend on a rapid response.
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