Estimates of atomic deuterium abundance and Lyman‐alpha airglow in the thermosphere of Jupiter

We have made calculations of the atomic D distribution in the thermosphere of Jupiter. The principal reactions determining the D abundance appear to be generation by reaction of H with vibrationally hot HD and loss by reaction of D with H 2 (υ=0,1) and CH 3 . The H and CH 3 distributions have been calculated using a 1‐D photochemical‐diffusion model with the column H constrained using the Lyman‐α airglow. For H 2 effective vibrational temperatures, T υ , between 1 and 4 times kinetic we find D columns between 4×10 11 and 2×10 13 atoms cm −2 . HD can be vibrationally excited due to VV energy transfer from H 2 (υ=1). Using a radiative transfer model with coupling of the H and D Lyman‐α lines we have calculated line profiles and total intensities across the Jovian disk and on the limb. For the above D columns and a H column ∼3.5×10 17 cm −2 , compatible with equatorial Lyman‐α airglow observations, the disk D intensity varies from 80 to 600 R for overhead Sun and viewing, whereas on the terminator the D maximum total intensity is ∼60 R at ∼860 km above the 1 bar level for the maximum D column.