Electromagnetic induction heating as a driver of volcanic activity on massive rocky planets

Abstract

<jats:p><jats:italic>Aims.</jats:italic> We investigate possible driving mechanisms of volcanic activity on rocky super-Earths with masses exceeding 3–4 <jats:italic>M</jats:italic><jats:sub>⊕</jats:sub>. Due to high gravity and pressures in the mantles of these planets, melting in deep mantle layers can be suppressed, even if the energy release due to tidal heating and radioactive decay is substantial. Here we investigate whether a newly identified heating mechanism, namely induction heating by the star’s magnetic field, can drive volcanic activity on these planets due to its unique heating pattern in the very upper part of the mantle. In this region the pressure is not yet high enough to preclude the melt formation.</jats:p> <jats:p><jats:italic>Methods.</jats:italic> Using the super-Earth HD 3167b as an example, we calculate induction heating in the planet’s interiors assuming an electrical conductivity profile typical of a hot rocky planet and a moderate stellar magnetic field typical of an old inactive star. Then we use a mantle convection code (CHIC) to simulate the evolution of volcanic outgassing with time.</jats:p> <jats:p><jats:italic>Results.</jats:italic> We show that although in most cases volcanic outgassing on HD 3167b is not very significant in the absence of induction heating, including this heating mechanism changes the picture and leads to a substantial increase in the outgassing from the planet’s mantle. This result shows that induction heating combined with a high surface temperature is capable of driving volcanism on massive super-Earths, which has important observational implications.</jats:p>