Emissivity and the fate of Pluto's atmosphere

We present a simplified model for seasonal changes in Pluto's surface-atmosphere system. The model demonstrates the potential importance of the solid-state phase transition between α-N₂ and β-N₂, and the accompanying change in emissivity, for predicting the seasonal bulk of Pluto's (and Triton's) atmosphere. Specifically, the model shows that under simplified but not unreasonable assumptions Pluto may have nearly the same atmospheric pressure at aphelion as it does now, near perihelion. The emissivity change which accompanies the α-β phase change should be included in the next generation of Pluto and Triton seasonal models for the purposes of understanding the evolution of their atmospheres over seasonal and climatic timescales.