Insights on stellar rotation and magnetism from main-sequence solar like stars to red giants

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• Savita Mathur, Instituto de Astrofisica de Canarias
• Wednesday 14 October 2020, 14:00-15:00
• online .

If you have a question about this talk, please contact Silvia Toonen.

PhD meet & greet at 12.30

During the last 15 years, photometric data of large samples of stars have been collected thanks to space missions such as CoRoT, Kepler/K2 or TESS . The high quality of these data have allowed us to progress on different fields of astrophysics from exoplanet search to stellar physics, including galactic-archeology. The study of standing waves generated in stars proved that they carry crucial information to probe stellar interiors. The asteroseismic analysis of the the aforementioned data opened a window on the interior of solar-like stars with an external convective envelope. For instance, it is possible to measure the depth of these convective envelopes in main-sequence solar-like stars or to determine the rotation rate of the core of subgiants and red giants, showing that those rates are much slower than what is predicted by standard solar models.

Understanding the transport of angular momentum is crucial to better determine the stellar ages when using stellar evolution models. More than 40 years ago, Skumanich (1972) showed how rotation and magnetic activity decreased with the age of a solar-like star. While this result was based on the study of young cluster stars, later observations of other clusters, still younger than the Sun, agreed with this age-rotation or “gyrochronology” relationship. With more recent studies based on Kepler data, this empirical relation does not seem to hold, opening new questions on stellar dynamics evolution.

In this talk, I will focus on targets from solar-like stars to red giants where rotation and magnetism could be measured with photometric data. I will show how the photometric data of Kepler is providing key information on the understanding of angular momentum transport in stars and of magnetic activity at different evolutionary stages of a star like the Sun.

This talk is part of the Astrophysics Talks Series series.

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• Astrophysics Talks Series
• Bham Talks
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