Speaker: Ian Crossfield (University of Kansas)

Title: Discovery and Characterization of sub-Neptune Exoplanets

Abstract: The discovery and characterization of Hot Jupiters -- gas giant 
planets on few-day orbits -- was the subject of the latest Nobel 
Prize, and has been a fecund area of research since these planets 
were discovered a quarter-century ago.  However, these planets 
are intrinsically rare: much more common are planets roughly the 
size of Neptune and smaller, the so-called sub-Neptunes and 
super-Earths.  These smaller worlds represent the typical end 
product of the star and planet formation process, yet to date few 
have been subjected to detailed scrutiny beyond their bulk 
properties (mass, radius, and density).  I will describe the 
large numbers of new sub-Neptunes discovered in recent years by 
space-based transit photometry, and discuss some of our emerging 
insights into their atmospheric structure and composition.