Joint Astrophysics Colloquium

Extrasolar Planets and the Search for Habitable Worlds

Sara Seager

MIT

Over 300 exoplanets are known to orbit nearby stars. Now that their existence is firmly established, a new era of “exoplanet characterization” has begun. A subset of exoplanets —  called transiting planets — pass in front of their stars as seen from Earth. Transiting planets have immeasurably changed the field of exoplanets because their physical properties, including average density and atmospheric thermal emission, can be now be routinely measured. I will summarize the observations and their interpretation of over fifty transiting exoplanets. I will discuss how the race to find habitable exoplanets has accelerated with the realization that “big Earths” around small stars can be both discovered and characterized with current technology. These ideas will lead us down a path to the ultimate goal of finding and identifying Earth twins.