Scientific Colloquium
December 14, 2007






THE JOHN BAHCALL MEMORIAL LECTURE
John Bahcall



GEOFFREY MARCY
UNIVERSITY OF CALIFORNIA, BERKELEY
Marcy photo

"Properties of Exoplanets:  Orbits, Interiors, and Origins"

Doppler measurements of 2000 nearby stars reveal 250 orbiting planets.
The masses range from 20 Jupiter-masses to nearly 5 Earths,
with a distribution favoring low mass.   The orbits reveal a
range of semimajor axes and eccentricities that inform theory.
Giant planets beyond 20 AU can be sensed, with implications for
imaging efforts.   Transiting planets constrain their
interior structure and chemical composition, influencing planet
formation models.


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