Professor James Lattimer
Department of Physics and Astronomy
7:30 pm Room 001 ESS Building
Friday, September 4, 2009

When Neutron Stars Collide

The collision of two neutron stars might seem like one of the most unlikely events possible. After all, a neutron star is no more than 20 miles across while space is vast. Yet it's been estimated that about a million of these events occur every year in the observable universe. For the most part, these mergers occur in binaries containing two neutron stars whose orbits are decaying through the emission of gravitational radiation. In fact, half a dozen systems have been observed so far in our Galaxy alone that will merge in less than a few billion years (one will merge in only 85 million years, a cosmic blink). These mergers are not only fun to model, but they are probably of great consequence. They are likely to be the most prodiguous sources of gravitational radiation that will be detected by the advanced LIGO gravitational wave detector. They could likely be the source of the short, hard gamma ray bursts that cannot be associated with supernovae like the majority of gamma ray bursts. And neutron star mergers might be a major source of the r-process elements, comprising about half of elements heavier than iron, which are produced in cosmic accelerators of high neutron fluxes.

Professor Lattimer has been teaching and researching at Stony Brook for thirty years. Most of his recent research has been in the area of nuclear astrophysics, the coupling of nuclear physics with astronomy. He lives with his family in East Setauket, where he also pursues the hobby of ferroequinology.