X‐ray imaging of the solar wind—Mars interaction

Wherever the solar wind meets a neutral atmosphere, X‐rays are emitted by charge‐exchange processes between heavy solar wind ions and the neutrals. Using an empirical model of the proton flow near Mars we present computer simulations of X‐ray emissions from this charge‐exchange process in Mars' exosphere. We also discuss implications for remote sensing. Here we show that the total X‐ray luminosity near Mars from charge‐exchange is greater than 1025 eV/s for typical solar wind conditions. This flux is large enough to be detected by an X‐ray satellite in Earth orbit. Thus, Mars belongs to a new class of X‐ray objects in the sky, together with other non‐magnetized planets, such as Venus.