A PROFILE ANALYSIS OF RAMAN-SCATTERED O VI BANDS AT 6825 angstrom AND 7082 angstrom IN SANDULE'S STAR

Abstract

We present a detailed modeling of the two broad bands observed at 6825 and 7082 angstrom in Sanduleak's star, a controversial object in the Large Magellanic Cloud. These bands are known to originate from Raman scattering of O VI lambda lambda 1032 and 1038 photons with atomic hydrogen and are only observed in bona fide symbiotic stars. Our high-resolution spectrum obtained with the Magellan Inamori Kyocera Echelle spectrograph at the Magellan-Clay Telescope reveals, quite surprisingly, that the profiles of the two bands look very different: while the Raman 6825 angstrom band shows a single broad profile with a redward extended bum, the Raman 7082 angstrom band exhibits a distinct trip-peak profile. Our model suggests that the O VI emission nebula can be decomposed into a red, blue, and central emission region from an accretion disk, a bipolar outflow, and a further compact, optically thick region. We also perform Monte Carlo simulations with the aim of fitting the observed flux ratio F (6825)/F (7082) similar to 4.5, which indicates that the neutral region in Sanduleak's star is characterized by the column density N-HI similar to 1 x 10(23) cm(-2).