Nonthermal atmospheric escape from Mars and Titan

Energy flux spectra and particle concentrations of the hot O and N coronae from Mars and Titan, respectively, resulting primarily from dissociative recombination of molecular ions, have been calculated by means of a Monte Carlo method. The calculated energy flux spectra lead to an escape flux ϕesc ≈ 6×106 cm−2 s−1 for Mars and ϕesc 2×106 cm−2 s−1 for Titan, corresponding to a mass loss of about 0.14 kg/s for Mars and about 0.3 kg/s for Titan. (The contribution of electron impact ionization on N2 amounts to only about 25% of Titan's mass loss.) Mass loss via solar and magnetospheric wind is also estimated using newly calculated mass loading limits. The mass loss via ion pickup from the extended hot atom corona for Mars amounts to about 0.25 kg/s (O+) and for Titan to about 50 g/s (N2+ or H2CN+). Thus, the total mass loss rate from Mars and Titan is about the same, i.e., 0.4 kg/s.