Second-Order Asymptotic Approximations for Stellar Nonradial Acoustic Modes

The problem of linear, nonradial pulsations in spherical stellar models is reconsidered using second-order asymptotic expansions. Acoustic modes of high radial order and low degree are investigated without making use of the so-called Cowling approximation. Detailed solutions are obtained for these modes. Comparison is made between these new results and those obtained when Cowling's approximation has been used. The connection between Olver's asymptotic theory and the so-called plane-wave method is also discussed. 17 refs.