AAS Meeting #193 - Austin, Texas, January 1999
Session 64. Pulsating Stars
Display, Friday, January 8, 1999, 9:20am-6:30pm, Exhibit Hall 1

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[64.05] Non-linear hydrodynamical simulations of delta Scuti star pulsations

M.R. Templeton (New Mexico State University), J.A. Guzik (Los Alamos National Laboratory), B.J. McNamara (New Mexico State University)

We present the initial results of non-linear hydrodynamic simulations of the pulsation modes of delta Scuti stars. These models use the Ostlie and Cox (1993) Lagrangian hydrodynamic code, adapted to use the most recent OPAL (1996) opacities, the Stellingwerf (1974) periodic relaxation method of obtaining stable limit cycle pulsations, and time-dependent convection. Initial tests of first- and second-overtone pulsation models are consistent with the models of Bono, et al (1997) showing asymmetric lightcurves for first overtone rather than fundamental pulsations. Future modeling work will test several stellar models with varying masses, ages, metal and helium abundances and envelope abundance gradients. Ultimately, we hope to determine the role that abundances and, more specifically, helium abundance gradients in delta Scuti envelopes play in light curve shape. This work will be applied to a test sample of known radially-pulsating delta Scuti field stars and the newly-discovered delta Scuti/SX Phoenicis variables in the Galactic Bulge.


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