Paul Butler (Carnegie Institute of Washington)

Date: Thu. April 27th, 2017, 4:00 pm-5:00 pm
Location: Rockefeller 301

Planets Around Nearby Stars

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.