Lava Planets

Nicolas Cowan
Dept. of Earth and Planetary Sciences,
McGill University

Abstract

Three decades of searching  have revealed that planets are abundant in the Galaxy, but most are unlike those found in the Solar System. Lava planets are among the strangest exoplanets discovered so far. Their bulk density suggests an iron core surrounded by a rocky mantle, like Earth. But they orbit so close to their star that they are tidally locked into  synchronous rotation: their permanent dayside is hot enough to melt —and vaporize— rock, while their nightside is expected to be cold and airless. Until lava planets were discovered, nobody had imagined the wild geophysics of such an asymmetric world: supersonic silicate winds, and a permanent, hemispheric magma ocean. I will review current scenarios for the formation, interior structure, and atmosphere of lava planets, and how we are pushing back the boundaries of our ignorance with numerical simulations and astronomical observations.