Lynn Buchele (Belgium)
lynn.buchele @ h-its.org
Structural Inversions of Solar-like Oscillators
In the quest to understand how stars work, astronomers have developed many techniques for extracting as much information as possible from the light that reaches our telescopes. One of these techniques is asteroseismology which uses the small variations in light from a star, caused by oscillations of the stellar material, to probe the internal structure of the star. These oscillations, primarily observed using space-based telescopes such as Kepler or TESS, provide a very detailed test of our current stellar models. What these tests reveal is that even our best stellar models don't match exactly the oscillations we observe. From a modeling perspective, one way to bridge this knowledge gap is to run many stellar models with that include different treatments of the physics occurring (convection, overshoot, element diffusion, etc) and then compare these grids to observations to find the best fitting set of input physics.
There is however another approach. Since the oscillations we observe in stars carry information about their internal structure and the calculated oscillations of our stellar models do the same, then the difference between our observed and calculated frequencies carries information about the differences between real stars and our models. The technique of stellar structure inversions seeks to get this information out. Inversions of the structure of our sun are possible to carry out with a high level of precision, however inversions of other stars are more difficult. The task becomes even harder for stars later in their evolution (sub-giants and red giants) as mixed modes, oscillations which carry information about both the stellar core and envelope, become more prominent. My project seeks to preform structure inversions on a variety of solar-like oscillators, beginning first with main sequence stars and then moving to sub-giant and red giant stars.
Supervisor: Saskia Hekker (HITS)