Jim Fuller

Monday, December 4, 2017
4:00 pm

Kuiper Space Sciences, Room 312

Institution: Caltech
Host: Isamu Matsuyama

Surprising Impacts of Gravity Waves

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
appreciated. For instance, Kepler asteroseismic data has revealed gravity modes
in thousands of red giant stars, providing unprecedented measurements of core
structure and rotation. I will show how gravity modes (or lack thereof) can also
reveal strong magnetic fields in the cores of red giants, and I will demonstrate that
strong fields appear to be common within “retired” A stars but are absent in their
lower-mass counterparts. In the late phase evolution of massive stars approaching
core-collapse, vigorous convection excites gravity waves that can redistribute huge
amounts of energy within the star. I will present preliminary models of this process,
showing how wave energy redistribution can drive outbursts and enhanced mass loss
inthe final years of massive star evolution, with important consequences for the
appearance of subsequent supernovae.