Professor James Lattimer
Department of Physics and Astronomy
7:30 pm Room 001 ESS Building
Friday, September 5, 2008

Now You See Them, Now You Don't: What Transits Can Tell Us About Extrasolar Planets

Over 300 extrasolar planets have been found to date. Most of them have been found using the "Doppler wobble" technique, in which Doppler shifts from their orbital motions around their parent stars are observed. However, several other techniques have also been utilized to find these planets, including microlensing, direct imaging, timing and transits. This talk will focus on the detection of extrasolar planets using the transit technique, in which sensitive photometry is used to measure the small decrease in brightness (about 1%) of a star when a planet passes in front of it. This situation requires that the planet's orbit around the star nearly coincides with the line-of-sight to the star, so only a small fraction of extrasolar planets can ever be discovered in this way. Nevertheless, the transits themselves reveal important information about the occulting planet that none of the other techniques can reveal, such as the diameters of the planets and, in some cases, the compositions and temperatures of their atmospheres.

Prof. Lattimer has taught and researched at Stony Brook for nearly 30 years, and has received awards from the Alfred B. Sloan and John Simon Guggenheim Memorial Foundations. He has also been elected a Fellow of the American Physical Society. His research primarily involves nuclear astrophysics, in particular, the study of neutron stars and supernovae.