Top panel: transit radius vs. surface gravity of a sample of transiting Jupiter-sized exoplanets around main-sequence stars (black data points). The red data points are the sub-sample of transiting exoplanets with zero-albedo equilibrium temperatures below 1000 K. The single outlier is Kep-447b (see the text). Bottom panel: the same sub-sample, but color-coded by mass. The red, green, blue, and cyan points are for ﹩\lt 0.8\,{M}_{{\rm{J}}}﹩, ﹩0.8\lt M\lt 1.2\,{M}_{{\rm{J}}}﹩, ﹩1.2\lt M\lt 2\,{M}_{{\rm{J}}}﹩, and ﹩\gt 2\,{M}_{{\rm{J}}}﹩, respectively. Data taken from http://www.exoplanets.org (Han et al. 2014).