Probing the Physics of Planetary Volatiles

Any chemical species capable of moving or changing phase at the conditions which exist on or near a planetary surface is a volatile. While many volatiles are found in the atmospheres of planets, surface-atmosphere interactions with condensed phases can be especially interesting. These deposits may represent an atmosphere that no longer exists but which might arise again in the future.  In this talk, I will discuss the evolution of ice reservoirs on Pluto and the Moon. On Pluto, methane exists within the atmosphere and on the surface in parallel ridges sculpted by the sun at high elevations. On the Moon, water delivered from diverse sources moves through the exosphere to deposit in cold traps within the permanently shadowed regions. In both cases, I will discuss how spacecraft have characterized these deposits and our efforts to learn more about them. Lastly, I will generalize these examples to consider how volatiles can be accumulated by planetary bodies of any size around any star.

Speaker: John Moores, York University