Quark stars have eigenfrequencies and are typically approximated to be at zero temperature. In this thesis, we determine the stability of radially oscillating quark stars at finite temperatures by calculating the star’s eigenfrequencies. We also illustrated the influence of temperature and bag constant on eigenfrequency. For a range of stable stellar masses at zero temperature we find for a bag constant of 55 MeV/fm³, an eigenfrequency range of 203.4 to 0 kHz² and for a bag constant of 90 MeV/fm³, an eigenfrequency range of 615.9 to 0 kHz². Having a larger bag constant causes the mass peak to be smaller and makes the stars more dense and thus harder to compress. If they are harder to compress, their eigenfrequencies will be larger. At finite temperatures there is a thermal contribution to the equation of state which impacts the mass peak and thus the density of the star. This leads to a change in eigenfrequency. For a range of stable stellar masses at a temperature of 50 MeV, we find for a bag constant of 55 MeV/fm³, an eigenfrequency range of 171.4 to 0 kHz² and for a bag constant of 90 MeV/fm³, an eigenfrequency range of 609.7 to 0 kHz². For a range of stable stellar masses at a temperature of 100 MeV, we find for a bag constant of 55 MeV/fm³, an eigenfrequency range of 221.4 to 0 kHz² and for a bag constant of 90 MeV/fm³, an eigenfrequency range of 747.3 to 0 kHz². We have also seen that quark stars become unstable after the mass peak, which leads to the conclusion that the mass peak is related to the stability of a star.
