The cosmogenic production of phosphorus in the atmosphere of Venus

Abstract

A model of the Venusian atmosphere examines the production of phosphorus via interactions of cosmic rays and solar particles with sulfur and argon. It is estimated that the stable isotope Phosphorus-31 has been generated between 23.7 and 67.7 micrograms per day given the present atmosphere of Venus and the variability in the flux of cosmic rays. If the maximum amount of phosphorus were converted into phosphine, the corresponding cosmogenic upper limit for phosphine production would be 74.3 +/− 0.8 micrograms per day. Assuming the maximum phosphorus is converted into phosphine with no losses over time, our simulations show that the cosmogenic production of phosphine cannot account for the 20 ppb concentrations reported by Greaves et al. (2020). Gamma rays and neutrons resulting from cosmic ray interactions are also examined just after they leave the planet.