Speaker: Dr. Joyce Guzik 

X-Theoretical Design Division

Testing Stellar Interior Physics via Stellar Pulsations

Abstract: 

Stars of nearly every type and evolutionary state have been discovered to show intrinsic variability, either in brightness or in spectral line profiles.  These pulsations or oscillations fortunately are not just surface phenomena, but can in principle be used to infer stellar interior structure and test stellar models--a field of research known as asteroseismology.   Since 2009, the NASA Kepler spacecraft’s long time-series photometric observations have characterized pulsation frequencies for thousands of stars to high precision, revealing many new variable stars and motivating new questions.

This talk will focus on the seemingly mundane stars fusing hydrogen to helium in their cores, including the Sun. I will discuss the types of variability, illustrated by Kepler light curves, and the possible causes of variability.   I hope to give a picture of the physical processes occurring in these stars, to discuss the input for stellar modeling that is being tested by the observations, and to highlight a few of the unsolved problems.