Physics Colloquium: "The Compositions of Small Planets"

Date: 
Mon, 28/12/201512:00-13:30
Location: 
Rothberg Hall (Next to the National Library of Israel)
Lecturer: Prof. David Charbonneau
Affilliation: Department of Astronomy,
Harvard University
Abstract:
The NASA Kepler Mission has demonstrated
that planets larger than Earth yet smaller than
Neptune are common around Sun-like stars.
Although Kepler determined the physical sizes
of hundreds of such worlds, we know virtually
nothing about their masses and, by inference,
their compositions. For the past three years, we
have been observing a carefully selected subset
of these super-Earths with the HARPS-N
instrument, an ultra-stable fiber-fed high-
resolution spectrograph built for this very
purpose. I report on the constraints on the
planetary compositions, and address the
transition from rocky planets, composed of rock
and iron, to Neptune-like worlds, which have
accreted an envelope of primordial H/He gas.
I will explain the essential role of the NASA
Transiting Exoplanet Survey Satellite (TESS),
scheduled for launch in 2017.