Hydrodynamic escape of nitrogen from Pluto

Abstract

Hydrodynamic escape of nitrogen from Pluto is studied by solving time‐dependent hydrodynamic escape equations that treat the spatial distribution of EUV energy deposition realistically. Simulations show that the N2 hydrodynamic escape rate is ∼1 × 1028 molecules s−1 when Pluto is at 40 AU (its average orbital location) and solar activity level is at minimum. The N2 hydrodynamic escape rate is ∼2 × 1028 molecules s−1 when Pluto is at its perihelion (30 AU) and solar activity level is at maximum. Through hydrodynamic escape, Pluto may have lost ∼0.5% of its total mass over the age of the solar system. Comet‐like interactions may occur between Pluto's atmosphere and the solar wind flow, which may be observed by the New Horizon mission.