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In his PhD dissertation Martin Bo Nielsen performs observational studies of rotation in stars like the Sun. The interior rotation in stars is thought to be one of the driving mechanisms of stellar magnetic activity, but until now this mechanism was unconstrained by observational data.
NASA's Kepler space mission provides high-precision observations of Sun-like stars which allow rotation to be inferred using two independent methods: asteroseismology measures the rotation of the stellar interior, while the brightness variability caused by features on the stellar surface trace the rotation of its outermost layers. By combining these two techniques Martin Bo Nielsen was able to place upper limits on the variation of rotation with depth in five Sun-like stars. These results suggest that the interior of other Sun-like stars also rotate in much the same way as our own Sun.
List of contents
Introduction.- Rotation Periods of 12 000 Main-sequence Kepler Stars.- Rotational Splitting as a Function of Mode Frequency for Six Sunlike Stars.- Constraining Differential Rotation of Sun-like Stars from Asteroseismic and Starspot Rotation Periods.- Discussion: Constraining Interior Rotational Shear.- Appendices.
About the author
Martin Bo Nielsen received his B.Sc and M.Sc degrees from Aarhus University in Denmark, during which he spent one year as a student support astronomer at the Nordic Optical Telescope on La Palma, Spain. This was followed by a PhD on the topic of differential rotation in Sun-like stars, at Georg-August-Universität in Göttingen, under the supervision of Prof. Laurent Gizon and Dr. Hannah Schunker.
Summary
In his PhD dissertation Martin Bo Nielsen performs observational studies of rotation in stars like the Sun. The interior rotation in stars is thought to be one of the driving mechanisms of stellar magnetic activity, but until now this mechanism was unconstrained by observational data.
NASA’s Kepler space mission provides high-precision observations of Sun-like stars which allow rotation to be inferred using two independent methods: asteroseismology measures the rotation of the stellar interior, while the brightness variability caused by features on the stellar surface trace the rotation of its outermost layers. By combining these two techniques Martin Bo Nielsen was able to place upper limits on the variation of rotation with depth in five Sun-like stars. These results suggest that the interior of other Sun-like stars also rotate in much the same way as our own Sun.
