Date of Award

Spring 2007

Document Type

Thesis

Department

Mathematics, Engineering & Computer Science

Abstract

Studying aspects of nature unable to be measured or observed has been a problem in the field of astronomy. This study looks at the interiors of zero-age main sequence (ZAMS) stars and how they are studied, despite being several light-years away or more, by means of mathematical modeling. We introduce the equations of stellar structure key to establishing a model for the interior. Our assumptions were based on how density behaves in the interiors, which include constant and linear density change with respect to stellar radii. We used observational data from a range of spectral types to compare to our models. Stellar interiors according to the constant density model have decreasing core density, pressure and energy generation with respect to solar mass, which was expected to increase with increasing stellar mass. As predicted, core temperature and total luminosity increase sharply with increasing stellar mass and the total luminosity matches closely with the observational data for each spectral class. The linear density model actually gives less accurate results for total luminosity, making our first model better for calculating luminosity. All core conditions for each star increased, but density and pressure still dropped with respect to increasing stellar mass. With this information and the fact that our results were more accurate with low-mass stars, we conclude that density must change in more complex ways for high-mass stars with a steep gradient near the core. Such results point out the importance of using precise numerical methods in modeling stellar interiors.

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