Surprising Impacts of Gravity Waves

Prof. Jim Fuller (Caltech)
February 27, 2018 - 4:00pm


Gravity waves are low frequency fluid oscillations restored by buoyancy forces in planetary and stellar interiors. Despite their ubiquity, the importance of gravity waves in evolutionary processes and asteroseismology has only recently been fully appreciated. I will discuss gravity waves in two very different astrophysical contexts: the interiors of giant planets and the cores of red giant stars. Gravity modes appear to have been detected in the planet Saturn using its rings as a seismograph, revealing crucial details about the evolution of giant planets. These modes could also be responsible for the outward tidal migration of giant planet moons. Kepler asteroseismic data has revealed gravity modes in thousands of red giant stars, providing measurements of core rotation that are faster than the surface rotation, but slower than expected. Moreover, gravity modes (or lack thereof) can reveal strong magnetic fields in the cores of red giants, and strong fields appear to be common within "retired" A stars. I will discuss the implications of these results for compact remnants of all types.