AAS 198th Meeting, June 2001
Session 47. Variable and Binary Stars - Spectroscopy
Display, Tuesday, June 5, 2001, 10:00am-6:30pm, Exhibit Hall

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[47.01] FUSE Observations of Accretion Processes in TT Hya

G.J. Peters (USC), R.S. Polidan (NASA/GSFC), D.E. Lynch (GST)

The interacting binary TT Hya (B9.5Ve + K1III-IV) was observed throughout totality on 2001 March 8 with the FUSE spacecraft to investigate the physical conditions in its apparent bipolar jet. The presence of this polar flow was inferred from prior UV spectropolarimetry with the HST/FOS that revealed a polarization of ~30% in the in the faint continuum of the B star that is scattered into our line-of-sight by free electrons in this region. Four FUSE observations, each of ~2400 s duration, were obtained at phases 0.981--0.985 (centered on second contact), 0.991--0.995, 0.001--0.005, and 0.011--0.015 (just before the end of totality). A stellar-like continuum is observed longward of 1000~Å\, upon which are seen prominent broad emission features of Fe~III (UV1, \lambda\lambda1122-32~Å) and C~III (UV 4, \lambda1176~Å) as well as possible weak O~VI (UV1, \lambda\lambda1032, 1038~Å) emission. The existence of the latter weak emission feature and possible variability in the emission lines and continuum throughout eclipse will be discussed. The stellar-like continuum must be scattered light from the circumstellar plasma, as the light from the B star is totally obscured. The FUSE observations will be compared with similar ones for V356~Sgr (B2V + A2II) and earlier ORFEUS-SPAS II observations of TT Hya taken earlier at three phases outside of eclipse.

GJP is grateful for support from NASA Grant NAG5-8978.

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