Exoplanets
Planets around other stars reveal that planetary systems are common and far more diverse than the Solar System alone suggested.
DetectionTransits, radial velocities and other methods reveal planets indirectly and sometimes directly.
DiversityObserved planets include hot Jupiters, super-Earths, mini-Neptunes and compact multi-planet systems.
AtmospheresSpectroscopy can constrain atmospheric composition for selected planets.
Formation cluesPopulation patterns test models of disk evolution, migration and planet assembly.