Eliot Quataert (Berkeley) gave the astrophysics seminar today. He spoke about the last years-to-days in the lifetime of a massive star. He is interested in explaining the empirical evidence that suggests that many of these stars cough out significant mass ejection events in the last years of their lives. He has mechanisms that involve convection in the core driving gravity (not gravitational) waves in the outer parts that break at the edge of the star. His talk touched on many fundamental ideas in astrophysics, including the conditions under which an object can violate the Eddington luminosity. For mass-loss driven (effectively) by excess luminosity, you have to both exceed (some form of) the Eddington limit and deposit energy high enough up in the star's radius that there is enough total energy (luminosity times time) to unbind the outskirts. His talk also (inadvertently) touched on some points of impedance matching that I am interested in. Quataert's research style is something I admire immensely: Very simple, very fundamental arguments, backed up by very good analytic and computational work. The talk was a pleasure!
After the talk, I went to lunch with Daniela Huppenkothen (NYU), Jack Ireland (GSFC), and Andrew Inglis (GSFC). We spoke more about possible extensions of things they are working on in more Bayesian or more machine-learning directions. We also talked about the astrophysics Decadal process, and the impacts this has on astrophysics missions at NASA and projects at NSF, and comparisons to similar structures in the Solar world. Interestingly rich subject there.