The Atmospheres of Small Exoplanets
Diana Dragomir - MIT Kavli Institute
The Kepler mission has revealed that planets with radii between 1 and 4 Earth radii are the most common class of planets in the galaxy, though no such planets are known to exist in our Solar System and little is known about how they form. These planets can theoretically have a wide range of compositions which we are just beginning to explore observationally. I will discuss how transmission and emission spectroscopy of these planets’ atmospheres allows us to explore the transition region between terrestrial planets and miniature gas giants, constrain their composition, and eventually shed light on their formation pathways. While the relative faintness of the exoplanet host stars in the Kepler field make such observations extremely challenging with currently available instruments, a handful of transiting super-Earths and Neptune-size exoplanets are within reach of existing facilities. I will present results from multi-directional efforts aiming to paint a thorough picture of these few planets’ atmospheres, using the Hubble and Spitzer Space Telescopes with some help from ground-based facilities. The TESS mission will discover many more small planets transiting bright stars, which will facilitate a statistical characterization of their atmospheres. By probing the atmospheres of the few accessible small planets available now, we can inform the direction to be taken by future atmospheric studies of this class of exoplanets, in particular with powerful but limited observing resources such as the James Webb Space Telescope and the Extremely Large Telescopes.
Coffee and Donuts will be served at 2:00pm in 4054 McPherson Lab.