Thermonuclear Supernovae: Stellar Explosions in Three Dimensions

A 2004 INCITE Project

This project, led by Tomasz Plewa of the Center for Astrophysical Thermonuclear Flashes at the University of Chicago, was awarded 2,700,000 processor hours. This project is a collaboration between scientists at the university and at Argonne National Laboratory studying the longstanding problem of thermonuclear flashes on the surfaces and interiors of compact stars. These phenomena are not only fascinating in and of themselves, but are also important for the light they shed on other fundamental questions in astrophysics: X-ray bursts for what they tell us about the masses and radii of neutron stars; classical novae for the contribution they make to the abundances of intermediate-mass elements in the galaxy, and for what they say about how the masses of white dwarfs change with time in close binary systems; and Type Ia supernovae for the contribution they make to the abundances of intermediate mass and heavy elements in the galaxy. Type Ia supernovae are also important for their crucial role as standard candles in determining the Hubble constant.

The group, according to researcher Timur Linde, expects to typically use 512 to 1024 processors, then use 4096 or more processors for their final calculations. So far the group has achieved unprecedented simulations of stars and supernovae using NERSC's computing resources.

"We have calculated three Type Ia supernova explosion models, including one octant model with 8 km resolution," Linde reported. "This was our test run on Seaborg, but it is worth mentioning that this run would already be state of the art in this field."

The group has also calculated one full-star model with 8 km resolution and 30 km ignition regions and one full-star model with 8 km resolution and 50 km ignition regions.

"These last two runs are the first of this kind ever calculated — no group other than ours has produced full-star simulations before," Linde said. "We are now moving to 4 km and 1 km resolution models, which will require at least 512 processors and possibly the whole system at times."

The simulations show the evolution of the surface of a thermonuclear flame during deflagration phase of the explosion of a Type Ia supernova star (see images below or click here for a movie of the simulation).

"This work is in progress. Right now we are in the process of studying the sensitivity of star explosions to initial conditions," Linde said. "By mid-summer we will run a very large simulation of one star explosion, which will require all of Seaborg's CPU resources."

For more details, see "Simulation may reveal the detailed mechanics of exploding stars," University of Chicago news release, April 28, 2004.

Last update: June 10, 2004