Characterizing a New Kind of Exoplanet: Low-Mass Low-Density Exoplanets
When: April 15, 2014 3PM PDT
NASA’s Kepler Mission has revealed that the most common size of planet in our galaxy may be those from 2-3 Earth radii. Such medium-sized planets are significantly more common on close-in orbits than Neptune and Jupiter-class giant planets. We have no analog for these planets in our solar system. To explain their size, most require a thin envelope of H/He gas, atop a core of high pressure rock and/or water. An example relatively close to home is planet GJ 1214b, which is 2.6 Earth radii and 6 Earth masses, and orbits a cool red dwarf star near the Sun. This planet has been extensively studied with the Hubble and Spitzer Space Telescopes. In this talk, Prof.Fortney will first discuss our current understanding of the composition and atmospheric physics of GJ 1214b, which is potentially a prototype for this class of low-mass low-density planets, and will describe the physical processes that may be common to this type of fascinating planets.