Physics Colloquium: Planets Around Nearby Stars

Dr. Paul Butler, Carnegie Institution for Science

Modern science began with Copernicus speculating that the Earth is a planet and that all the planets orbit the Sun. Bruno followed up by speculating that the Sun is a star, that other stars have planets, and other planets are inhabited by life. For this and other heresies, Bruno was burned at the stake in a public square in Rome in 1600. Astronomy and extrasolar planets were a really hot field at the time.

Over the past 20 years more than a thousand extrasolar planets have been found, first from ground-based precision Doppler and photometric transit surveys, and more recently by the Kepler space mission. We have concentrated on building precise Doppler systems to survey the nearest stars. Our systems at Lick, Keck, AAT, and Magellan have found hundreds of planets, including 5 of the first six planets, the first saturn-mass planet, the first neptune-mass planet, the first terrestrial mass planet, and the first multiple planet system.

In August we announced the discovery of a potentially habitable around the nearest star, Proxima Centauri, based on archival data from the ESO HARPS and UVES spectrometers reanalyzed with improved packages that we have written, and with a dedicated 2 month campaign of high cadence observing on HARPS. This discovery highlights the latest statistical evidence from Kepler and ground-based Doppler surveys that ~30% of stars have potentially habitable planets.

Tuesday, October 30, 2018 at 3:15pm

Regents Hall, 109
3700 O St. NW

Event Type

Academic Events


Students, Faculty/Staff


Georgetown College, Physics




Dr. Paul Butler, Carnegie Institution for Science

Event Contact Name

Edward Van Keuren

Event Contact Email

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