Alexander Heger is a new professor in the area of nuclear theory and cosmology. His research involves creating and running computer simulations of "massive stars" (those that are 10-1000 the size of the sun) from formation through nuclear burning phases.

"I like to say I blow up stars for a living." Heger explains that massive stars have comparatively short life spans, around 2.5 million years versus the 10 billion estimated for the sun. "Big stars are very bright and wasteful with their energy." In the final stage of a massive stars life, the nuclear burning stage, the star burns its fuel to heavier and heavier nuclei, which in turn produces the heavier elements in the universe. "I think it’s good to know where the gold is being made in the Universe," Heger kids. The goals of his research are the origins of the elements. "This information will help us put the entire picture together about how our own galaxy was formed." This area of study includes stellar rotation, how the elements were formed "nucleosynthesis" and the mechanics of supernovae.

Heger also studies very old stars, the so-called "population one" that formed 300 million years after the big bang. "This connects an old question to modern cosmology. How did the stars form?" To answer this question Heger matches abundance patterns of certain elements to models based on mass. With these "finger prints" physicists can tell a lot about the stars age, and how it formed. "With newer stars it’s more difficult because contributions from later stars come into the mix." Heger explains that we could not say what generation the sun is because of those contributions.

In order to create his simulations, Heger works with theoretical models of what should be in the first generational stars. He says that University of Minnesota physicist Keith Olive is one of the pioneering experts at making those models. The models use known quantities such as the "initial mass function" a principal that states that a certain number of stars of each mass are being made at any given time. To test the model physicists try to match observations of modern stars with similar "finger prints."

Heger says that there is still a fair bit that is unknown about nuclear reaction rates. “There are 283 stable nuclei. We should know them all eventually. Even with unstable nuclei there are a finite number which is not impossible to understand.” The more that is known about nuclei, physicists can provide additional checks on theory. Heger’s work is expanding in new directions as computer modeling becomes more sophisticated. He has a student currently working on building multi-dimensional simulations—sure to yield "explosive" results.