2016 Jan: Surveys for new planets using the transit and radial velocity techniques reveal the high frequency with which small, short-period planets occur around main sequence stars. However, only a few of these smaller planets can be easily observed to characterize their atmosphere; even fewer are known around low-mass M stars, though these planetary systems may be the most common in the Galaxy. Our team has discovered three small planets orbiting a bright, nearby M star using data collected by K2, the re-purposed Kepler spacecraft. These new planets likey straddle the transition region between rocky and increasingly gas-dominated compositions. Download the paper or read all about it here.
More recently, our team announced our discovery of hundreds of planet candidates from K2, including over 100 fully validated planets. These true, bona fide planets (no longer mere candidates!) provide an excellent laboratory for measuring planet masses (via RVs and TTVs), atmospheric composition (with HST and JWST), and for studying planetary habitability. Read all about the new results online here, here, here, or here, or read the full paper here.
Also of interest is my recent invited review
of Exoplanet Atmospheres. Detailed atmospheric characterization of
exoplanets provides the best hope for
distinguishing their makeup, and the only hope for
understanding the interplay between initial composition, chemistry,
dynamics and circulation, and disequilibrium processes. This
article gives an observer's perspective on the current understanding
of extrasolar planet atmospheres prior to the considerable advances
expected from the next generation of observing facilities. Atmospheric
processes of both transiting and directly imaged planets are
discussed, including molecular and atomic abundances, cloud
properties, thermal structure, and planetary energy budgets. In the
future we can expect a continuing and accelerating stream of new
discoveries, which will fuel the ongoing exoplanet revolution for many
years to come.
I am a Sagan Fellow in the Astronomy and Astrophysics Department at the University of California, Santa Cruz. My interests lie in exoplanet formation, composition, detection, and characterization, and the development of instrumentation to further those pursuits. I am currently studying extrasolar planets using both photometry and high-resolution spectroscopy from the ground and space. I have worked for two years at UA's Lunar and Planetary Laboratory in Tucson, for two years at the MPIA in Heidelberg, Germany and for three years at the Jet Propulsion Laboratory. I received my doctorate from UCLA. I also maintain an online repository of useful Python computing tools.
Ian J. M. Crossfield
Astronomy and Astrophysics Department
UC Santa Cruz 1156 High Street
Santa Cruz, CA 95064