UNC-CH Physics and Astronomy Thesis Proposal Presentation

Reece Boston

White dwarf stars occupy a region of parameter space just between relativistic and Newtonian physics, being the least compact of the compact objects. In terms of gravitational field strength they lie somewhere midway between a neutron star and a main sequence star. For most astronomical purposes, it is usually sufficient to ignore general relativity when studying a white dwarf star. In the modern age of space-based astronomy, the K2, TESS and LISA missions require revisiting the relativistic behavior of white dwarfs. The K2 and TESS missions observe light curves of white dwarfs over long time scales, producing measurements of pulsation periods with fractional errors below the relativistic corrections to the period. The LISA mission will observe millihertz gravitational wave signals. One major source for LISA will be extreme mass-ratio inspirals (EMRIs), which produce gravitational radiation though the orbit of a solar-mass compact object around a supermassive black hole. One type of EMRI may involve a white dwarf as the companion. Both of these areas of study rely on knowledge of the internal eigenmodes of a white dwarf star. In my research, I have produced code capable of computing stellar models and their eigenmodes to very high numerical accuracy. For my dissertation, I will use this code to study the effects of general relativity on white dwarfs, both in terms of their internal eigenmodes and the way these eigenmodes respond to external tidal fields.