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J.M. Meyer (U. of Wisconsin & Maria Mitchell Obs.), K.H. Nordsieck (U. of Wisconsin), V. Strelnitski (Maria Mitchell Obs.)
Spectropolarimetry of the emission line star MWC 349 was carried out with the 0.9 m telescope at the Pine Bluff Observatory of the University of Wisconsin, in the spring, summer and fall of 2000, and with the 3.5m WIYN telescope, in the fall 2000. The wavelength range covered by the two telescopes was 4500 to 10,500 A and the spectral resolution approximately 10 A in both cases. With WIYN, it was possible to separate the close (2.4~arcsec) optical companion (B) of the main, emission line star (A). The companion is found to be an emission line star with prominent H\alpha plus CaII triplet emission lines. If the companion is assumed to have no significant intrinsic polarization, it is possible to determine accurately, for the first time, the interstellar polarization in the direction of MWC 349, and thus to determine accurately the intrinsic polarization of MWC 349A. The measured polarization of MWC349B is consistent with the interstellar polarization in the nearby association Cyg OBII. A preliminary analysis shows that (1) the main star has a strong intrinsic polarization, probably arising in the circumstellar disk; (2) polarization in the emission lines differs significantly from that in continuum and it changes from line to line; and (3) polarization of the emission lines and, at a lesser extent, of continuum, vary with a time scale of a few months. This project was partially supported by the NSF/REU grant AST-9820555.