ULTRAVIOLET SPECTROPOLARIMETRY OF 3 CLASSICAL NOVAE EARLY IN OUTBURST- EVIDENCE FOR ASPHERICAL SHELLS

The Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE) was use d to obtain the first ultraviolet (1450-3200 Angstrom) spectropolarime try of three classical novae, all of which had recently gone into outb urst (Nova Cir 1995, Nova Aql 1995, and Nova Cen 1995). All three nova e appear to have intrinsic polarization, with polarization changes acr oss emission lines or time-variable polarization, indicating that the ejecta were geometrically aspherical. A simple model is used to estima te the level of asphericity of the novae ejecta. Different emission li nes exhibit varying amounts of polarization, suggesting that they are formed in regions of differing geometry. In particular, the Mg II reso nance line in Nova Cir is more polarized than the continuum. This coul d be the first time that a polarized resonance line has been observed in a nova. (C) 1997 American Astronomical Society.