Lifetime of a transient atmosphere produced by lunar volcanism

Early in the Moon's history volcanic outgassing may have produced a periodic millibar level atmosphere (Needham and Kring 2017). We examined relevant atmospheric escape processes lifetime of such an atmosphere. Thermal rates were calculated as function mass for range temperatures including effect presence light constituent H2. Photochemical sputtering using estimates higher EUV plasma fluxes consistent with early Sun. The often used surface Jeans calculation carried out Vondrak (1974) is not applicable scale composition considered. show that solar driven non-thermal can remove CO on order ~1 Myr if average exobase temperature below ~350–400 K. However, UV/EUV absorption heats upper to > ~ 400 K thermal increasingly dominates loss rate, we estimated minimum 100's years considering energy limited escape.