Free Astronomy Magazine September-October 2016

ly-formed SEPTEMBER-OCTOBER 2016 K 2-33b, shown in this illustration, is the youngest fully-formed exoplanet de- tected to date. It makes a complete orbit around its star in about five days. These two characteristics combined provide ex- citing new directions for planet-formation theories. K2-33b could have formed on a farther out orbit and quickly migrated in- ward. Alternatively, it could have formed in situ, or in place. [NASA/JPL-Caltech]