Classification of exoplanets according to density

Considering probability distribution as a function of the average density ρ¯ computed for 424 extrasolar planets, we identify three log-normal Gaussian population components. The two most populous components at ?¯ ≃ 0.7 g/cc and ?¯ ≃ 7 g/cc are the ice/gas giants and iron/rock super-Earths, respectively. A third component at respectively. A third component ? 30 g/cc is consistent with brown dwarfs, i.e., electron degeneracy supported objects. We note presence of several extreme density planetary objects.