POSTER PAPER 9.04
FUSE Observations of a Mira Variable Star
Donald G. Luttermoser, Michael W. Castelaz
Institute: East Tennessee State University
Institute: Pisgah Astronomical Research Institute
Contact Email: lutter@etsu.edu
Abstract:
We have obtained a FUSE spectrum of the long-period variable (Mira-type) star
S Car. This observation gives us the opportunity to probe the
temperature-density structure the outer shocked region of the
atmosphere of this star using the hydrogen Lyman lines. We obtained an LWRS
spectrum on 25 May 2001 when this star was at optical light-curve phase 0.35.
We make flux comparisons between Lyman lines and UV emission lines obtained at
near coincident phases with the IUE. This is done to study the effect that the
radiation field from the inner, hotter shocks (where Mg II and
the Balmer lines form) have on the outer shocked region (where the Lyman lines
form). We also make comparisons to synthetic spectra from dynamic models
representative of this star. These NLTE radiative transfer calculations have
shown that the radiation field of the inner shocks dominate the ionization
throughout the entire atmosphere. The calculations also have shown that the
Lyman emission lines form in the outer reaches of the atmosphere where the
shocks are much weaker as they propagate outward.
Index Keywords: S Car; FUSE; NLTE Synthetic Spectra
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Manuscript submitted: 2001-Sep-04
"The Future of Cool-Star Astrophysics", 2003, Eds. A. Brown,
G. M. Harper, & T. R. Ayres.
Proceedings of 12th Cambridge Workshop on Cool Stars, Stellar Systems,
& The Sun,
© 2003 University of Colorado.