Ultraviolet Spectropolarimetry of the Massive Interacting \hfil\break Binary V356~Sgr

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Session 85 -- Binaries
Display presentation, Wednesday, 11, 1995, 9:20am - 6:30pm

[85.23] Ultraviolet Spectropolarimetry of the Massive Interacting \hfil\break Binary V356~Sgr

R.S.Polidan (LASP/GSFC), D.E.Lynch (GST \& U.Maryland), \hfil\break R.A.Downes (STScI), C.D.Keyes (STScI), S.N.Shore (IUSB)

We report on FOS spectropolarimetry in the 1300-1600\AA\ region of the interacting binary V356 Sgr. This binary system consists of a critically rotating B0/3 main-sequence band primary star and a Roche-lobe filling A2II star and has an orbital period of 8.896 days. Ultraviolet spectroscopic observations with IUE have shown that the system displays strong, broad emission lines of N V, Si III, Si IV, and Al III during the total eclipse (C IV is not seen because the circumstellar matter is composed of CNO processed material) but a relatively normal B0/3 spectrum without emission lines outside of eclipse. The FOS observations were obtained in October 1993 and were intended to provide spectropolarimetry of the star during the total eclipse. Unfortunately, due to a scheduling error, the observations occurred outside of eclipse at binary phase 0.10. Analysis of this single outside of eclipse observation indicates that linear polarization is present in the ultraviolet in V356 Sgr at this phase. A detailed description of the spectropolarimetric observations are presented along with models interpreting the observations.

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