Preview

PDF, English - main document Download (29MB) | Lizenz: Asteroseismic Structure Inversions of Solar-like Oscillators by Buchele, Lynn underlies the terms of Creative Commons Attribution 4.0

Abstract

The study of stars through their global oscillations, i.e., asteroseismology, has provided unprecedented insight into stellar interiors. One of the most powerful techniques of asteroseismology is that of structure inversions. This technique can localize and quantify differences in sound speed between a star and its best-fit model. These differences, then, are a direct test of the accuracy of our stellar models.

The first part of this thesis outlines the specifics of the inversion procedure and then applies it to 55 main-sequence stars observed by the Kepler mission with masses between 1 and 1.6 solar masses. This discussion is split into stars with radiative and convective cores. Overall, the inversions reveal that our best-fit models match the sound speed profile in around half of the stars studied. In the remaining half of the sample, there is an even split between cases where the model sound speed is too high and cases where it is too low.

The second part of this thesis explores whether current inversion techniques are suitable for subgiant stars. These stars exhibit mixed modes that are sensitive to deeper regions of stellar cores. As the sensitivity of these mixed modes changes on a very short timescale, obtaining reliable inversion results will require modifications to current techniques.