Thesis Topic: Optical interferometric imaging of rapidly rotating stars


Thesis Supervisor: Christian Hummel




Rapidly rotating stars display an uneven surface brightness profile due to gravity darkening. This can be modeled using Roche spheres and van Zeipel's law. However, deviations from theory exist and are best tackled observationally using interferometric imaging. Due to the small number of telescopes available in interferometric arrays, aperture coverage can beincreased using multi-channel observations over a wide range of wavelengths. An algorithm able to produce images from such data has been developed recently by C. Hummel and is need of further improvements.

Data of the rapidly rotating star Altair is available from the Navy Prototype Optical Interferometer and could be used to derive an image of the surface using the new imaging algorithm. Coherent integration of the visibility data requires additional algorithmic work ("global fringe fitting").

Therefore, the student should have an interest both in mathematical algorithms as well as in the astrophysics of stellar rotation.

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