Monday, May 4, 2020 - 16:00
Event Speaker: 
Eric Agol (UW)
Local Contact: 
Davide Lazzati

I will introduce the TRAPPIST-1 system, which is comprised of 
seven transiting, Earth-sized planets orbiting a very small 
star, about a tenth the size of our Sun in mass and radius. 
This system may yield the best chance of studying the atmospheric 
compositions of temperate, Earth-sized planets with the James 
Webb Space Telescope, and has become a focal point for the 
exoplanet and planetary science communities.  I will report on 
ongoing efforts by an international team to measure the masses, 
radii, densities, and orbits of the planets in this system with 
the Kepler and Spitzer Space Telescopes (RIP), HST, and ground-based 

I will describe the transit-timing technique, and the dynamical basis 
for measuring the planets' masses and orbital parameters.  The 
planets' compositions can be ascertained from dynamical modeling, 
and I will give an update on these efforts, and the implications for 
their compositions, for planet formation, and place this system in 
the context of measurements of other exoplanets' properties.  I will 
conclude by discussing future prospects for the study of this system 
and for finding others like it.

Refreshments will be offered half an hour before the colloquium in Weniger 379