
%0 Journal Article
%A Murphy, JO 
%T Structure of a Sequence of Two Zone Polytropic Stellar Models with Indices 0 and 1
%J Australian Journal of Physics
%D 1983/06/01
%V 36
%N 3
%P 453-462
%K 
%R https://doi.org/10.1071/PH830453B
%U https://www.publish.csiro.au/paper/PH830453B 
%X The structure and physical properties of a sequence of two zone polytropic stellar models, based on E-type composite analytical solutions of the Lane-Emden equation for indices n = 0 and 1, have been determined. The resulting models are characterized by an inner zone of constant density, corresponding to the n = 0 component, and a relatively small envelope with a steep polytropic density gradient and index n = 1. At the surface of these near uniform density composite configurations the physically significant condition p = 0 is always satisfied, a condition which is not fulfilled by the complete poly trope of index n = O. In each model the surface corresponds to the first zero of the associated composite function, which in turn is given by one of the higher order zeros of the E solution of the Lane-Emden equation for n = 1. The radial pulsational properties of these low central condensation type models have also been investigated with the relative amplitudes of radial displacement and density variation given as a function of radial distance for the first six modes of some selected models. Overall, these results establish that the radial displacement amplitudes are only significant in the n = 1 outer layer and accordingly the pulsations can be classified as essentially surface phenomena 
