Colloquium

New Ideas in the Theory of Core-Collapse Supernova Explosions

Professor Adam Burrows
University of Arizona

Wednesday, April 26, 2006   4:00 p.m.  NSH 118

(Refreshments at 3:30 p.m. NSH 284)

 

I will discuss a new mechanism for core-collapse supernova explosions that relies upon acoustic power generated in the inner core as the driver. In our recent 2D simulations, a strong advective-acoustic oscillation with a period of ~25-30 milliseconds (ms) arises ~200 ms after bounce. Its growth saturates due to the generation of secondary shocks, and kinks in the resulting shock structure funnel and regulate subsequent accretion onto the inner core. However, this instability is not the primary agent of explosion. Rather, it is the acoustic power generated in the inner turbulent region and most importantly by the excitation and sonic damping of core g-mode oscillations. An l=1 mode with a period of ~2-4 ms grows to be prominent around ~500 ms after bounce. The accreting protoneutron star is a self-excited oscillator. The associated acoustic power seen in our 11-solar-mass simulation is sufficient to drive the explosion. The angular distribution of the emitted sound is fundamentally aspherical. The sound pulses radiated from the core steepen into shock waves that merge as they propagate into the outer mantle and deposit their energy and momentum with high efficiency. The core oscillation acts like a transducer to convert accretion energy into sound. An advantage of the acoustic mechanism is that acoustic power does not abate until accretion subsides, so that it is available as long as it may be needed to explode the star. I will address the consequences of this new mechanism for supernova explosions, the r-process, pulsar kicks, supernova blast morphology, and the gravitational
radiation signatures of the deaths of massive stars.