A correlation between the metallicity, [M/H], and rest-frame Mg II equivalent width, W λ2796 r

Abstract. The mean energy W expended in a collision of electrons with atmospheric gases is a useful parameter for fast aeronomy computations. Computing this parameter in transport kinetic models with experimental values can tell us more about the number of processes that have to be taken into account and the uncertainties of the models. We present here computations for several atmospheric gases of planetological interest (CO 2 , CO, N 2 , O 2 , O, CH 4 , H, He) using a family of multi-stream kinetic transport codes. Results for complete atmospheres for Venus, Earth, Mars, Jupiter and Titan are also shown for the first time. A simple method is derived to calculate W of gas mixtures from single-component gases and is conclusively checked against the W values of these planetary atmospheres. Discrepancies between experimental and theoretical values show where improvements can be made in the measurement of excitation and dissociation cross-sections of specific neutral species, such as CO 2 and CO.

Aims. The aim of this work is to characterize the impact of the solar UV flux and of the electron precipitation on Jupiter's atmosphere and to study the H Lyman α intensity and spectral profile in Jupiter's aurorae. In particular we characterize the sensitivity of the line to the relevant input parameters. Methods. We use a multi-stream electron transport code solving the 1D Boltzmann equation and a Feautrier technique radiative transfer code. Results. We calculate ionization rate profiles of the main species of Jupiter's ionosphere and the heating rate due to electron precipitation, as a function of the energy of the precipitation. We also calculate the emission rate of Lyman α photons under auroral electron precipitation and the ensuing line profile. The profile exhibits a centre reversal which could be used as a diagnostic of Jupiter's auroral low-energy electron precipitation.