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Session 77 - Binary Stars.
Display session, Wednesday, January 15
The eclipsing, interacting binary system, V356 Sgr, provides a rare opportunity to directly examine the exposed core of a star for the signatures of nuclear processing. The system is composed of an A2II star which has previously undergone rapid mass transfer to its B3V companion.
We are examining a large number of IUE archival spectra obtained by Dr. Polidan at low and high dispersions with phase coverage through most of the orbit including the eclipse of the B star by the 2.5 times larger A star. UV low dispersion spectra of the individual stars have been obtained by appropriate manipulation of the eclipse and combined light spectra and by modeling of the scattered light in the system due to circumstellar material. New model atmosphere parameters different from previously reported values have been determined (Teff = 22,000 and 9000K, log g = 4.0 and 3.0 dex, respectively for the B and the A star). A preliminary analysis (in support of proposed Hubble STIS/FUV observations) of selected features in the high dispersion spectra at different orbital phases has begun. We are also examining the low dispersion spectra at different phases for evidence of ellipsoidal distortion and gravitational darkening.
This project is supported by a NASA JOVE grant to SUNY Oswego.
Program listing for Wednesday