Long-term surface temperature modeling of Pluto

NASA's New Horizons' reconnaissance of the Pluto system has revealed at high resolution the striking albedo contrasts from polar to equatorial latitudes on Pluto, as well as the sharpness of boundaries for longitudinal variations. These contrasts suggest that Pluto must undergo dynamic evolution that drives the redistribution of volatiles. Using the New Horizons results as a template, we explore the surface temperature variations driven seasonally on Pluto considering multiple timescales. These timescales include the current orbit (248 years) as well as the timescales for obliquity precession (peak-to-peak amplitude of 23° over 3 million years) and regression of the orbital longitude of perihelion (3.7 million years). These orbital variations create epochs of ;Extreme Seasons; where one pole receives a short, relatively warm summer and long winter, while the other receives a much longer, but less intense summer and short winter. We use thermal modeling to build upon the long-term insolation history model described by Earle and Binzel (2015) and investigate how these seasons couple with Pluto's albedo contrasts to create temperature effects. From this study we find that a bright region at the equator, once established, can become a site for net deposition. We see the region informally known as Sputnik Planitia as an example of this, and find it will be able to perpetuate itself as an ;always available; cold trap, thus having the potential to survive on million year or substantially longer timescales. Meanwhile darker, low-albedo, regions near the equator will remain relative warm and generally not attract volatile deposition. We argue that the equatorial region is a ;preservation zone; for whatever albedo is seeded there. This offers insight as to why the equatorial band of Pluto displays the planet's greatest albedo contrasts.