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Paper: Opacity and the Equation of State
Volume: 135, A Half Century of Stellar Pulsation Interpretations: a Tribute to Arthur N. Cox
Page: 254
Authors: Rogers, F. J.; Iglesias, C. A.
Abstract: Equation of state and opacity are basic physical input quantities needed to model stellar structure and pulsation. For many purposes, the weakly non-ideal plasma of ordinary stars can be treated using simple models. However, the recent tremendous increase in the range and accuracy of observations have made it quite clear that this fact can be misleading. For example, the small nonideal terms in the equation of state have a significant affect on the structure of small amplitude oscillations in the Sun. In contrast to the ideal gas contribution, sophisticated methods are required to obtain these corrections. Also, as is now well known, long-standing difficulties in understanding and modeling the observed large amplitude pulsations in several types of stars have argued for improved opacity calculations. The present talk will review recent improvements in the calculation of equation of state and opacity and describe briefly their effect on stellar models. Some suggested future improvements in the calculated input physics will also be given.
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