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How can we constrain stellar magnetic activity with seismology?

Event Details

Event Dates: 

Monday, February 10, 2014 - 4:00pm

Seminar Location: 

  • JILA Auditorium

Speaker Name(s): 

Savita Mathur

Speaker Affiliation(s): 

Space Science Institute, Boulder
Seminar Type/Subject

Scientific Seminar Type: 

  • Astrophysical & Planetary Sciences Seminar

Event Details & Abstract: 

The dynamo process is believed to drive the magnetic activity of stars like the Sun that have an outer convection zone. In these stars, magnetic activity cycles result from the interaction between rotation (in particular latitudinal differential rotation), convection, and magnetic field. Unfortunately, the detailed mechanism of this process is not completely understood. Large spectroscopic surveys such as the one led at the Mount Wilson in CaHK, observations in X-ray, and in UV have already allowed us to study magnetic activity of many other stars. In particular, they showed that there could be a relation between the rotation periods and the cycle periods and that different manifestations of magnetic activity variability can be observed: either a regular cycle, a non-regular variability or no temporal variation. Which conditions and properties of the stars govern these different behaviors? To better understand the detailed mechanism driving solar and stellar magnetic activity and to better constrain the 3D dynamo models, it is important to know the characteristics of the magnetic field, the property of the convection, and the rotation profile (internal and at the surface) of the stars. The study of other stars in different conditions (rotation periods, spectral types…) helps us to put the Sun into a broader context of stellar evolution.

While spectroscopy and spectropolarimetry allow us to study the magnetic field and its temporal variation, seismology plays a crucial role as it is the only tool that provides us stratified information on the structure and dynamics of the stars. In this talk I will show how helio- and astero-seismology complete the big picture of the stellar magnetic activity by presenting the recent results obtained with space missions such as CoRoT (Convection, Rotation, and Transits) and Kepler and that directly impact this topic.