August 7-10, 2017

Abstract

Heat-driven stellar g-mode pulsations: lessons from space photometry

Timothy Van Reeth (Institute of Astronomy, KU Leuven)

The study of gravity-mode pulsations provides a unique window into stellar structure and evolution for various types of stars. In intermediate-mass gamma Doradus stars and higher-mass slowly pulsating B-type stars, they trace the properties of the near-core regions in the deep stellar interior, thus giving us a direct measure of the convective core evolution, as well as the chemical mixing mechanisms in these stellar regions and the interior rotation profiles. In the evolved white dwarfs, the gravity-mode pulsations are more sensitive to the properties of the envelope, but also provide us with a measure of possible differential rotation and chemical stratification. Thanks to high-precision photometric observations with space missions such as CoRoT, Kepler, and BRITE, we are now able to investigate these pulsations in much more detail than what was previously possible with ground-based observations. Patterns in the pulsation periods are readily detected. Over the last couple of years, this has led to significant results in this field, such as detections of differential rotation, and observational constraints on the convective core size and the efficiency of the chemical mixing processes for selected targets. Despite the BRITE constellation's humble set-up, its data have already contributed to this field. Thanks to these and other observations, our understanding of gravity-mode pulsations continues to improve. In future, it will likely provide us with insights in other aspects that are currently not well understood, such as convection and magnetic fields.

Mode of presentation need to be confirmed by the SOC