HIGH-RESOLUTION CORONOGRAPHIC IMAGING AND SPECTROPOLARIMETRY OF THE HR CARINAE NEBULA

We present multicolor coronographic imaging and optical spectropolarimetry of the Luminous Blue Variable HR Car. The images reveal the presence, in both Hα and [N II] filters, of a filamentary nebula characterized by bipolar, nearly point-symmetric structure, similar to some well-known planetary nebulae. The nebular filaments, which extend to 18″ from the star, appear to originate from a central brighter, compact structure which envelops HR Car, and has a size of ∼8′. From the emission lines flux, we estimate the overall mass of ionized gas in the nebula to be ∼2.1script M sign⊙. We also find evidence for the presence of intrinsic polarization in HR Car from the change of polarization at the Hα emission line with respect to the continuum. This result implies that the scattering material situated close to the star is not distributed with a spherical symmetry. From the Hα line-to-continuum vector we deduce an intrinsic polarization of (0.39%±0.02% with a position angle of (30°±1°) at Hα, and a large interstellar foreground polarization of (3.70%±0.02%) with a position angle of (127.9°±0.1°). HR Car is the third Luminous Blue Variable in which asymmetries of the circumstellar material on a small distance scala are found rom spectropolarimetry to agree with the large scale morphology, revealed by coronographic imaging. © 1995 American Astronomical Society.