History of Water Loss and Atmospheric O2 Buildup on Rocky Exoplanets near M Dwarfs

Abstract:

It is recently proposed that early stellar luminosity evolution of M dwarfs leads to severe water loss and the buildup of massive O₂ atmospheres on rocky exoplanets in the habitable zone of these stars if interactions of such O₂ atmospheres with planetary surfaces are inefficient. Here we show that the existence of a massive O₂ atmosphere on such exoplanets depends on stellar XUV properties, the mass of the exoplanets, and most importantly the initial planetary water inventories.