Combining stellar occultation observations probing Pluto's atmosphere from 1988 to 2013 and models of energy balance between Pluto's surface and atmosphere, we conclude that Pluto's atmosphere does not collapse at any point in its 248-year orbit. The occultation results show an increasing atmospheric pressure with time in the current epoch, a trend present only in models with a high thermal inertia and a permanent N2 ice cap at Pluto's north rotational pole.
Cite
@article{arxiv.1309.0841,
title = {Pluto's Atmosphere Does Not Collapse},
author = {C. B. Olkin and L. A. Young and D. Borncamp and A. Pickles and B. Sicardy and M. Assafin and F. B. Bianco and M. W. Buie and A. Dias de Oliveira and M. Gillon and R. G. French and A. Ramos Gomes and E. Jehin and N. Morales and C. Opitom and J. L. Ortiz and A. Maury and M. Norbury and F. B. Ribas and R. Smith and L. H. Wasserman and E. F. Young and M. Zacharias and N. Zacharias},
journal= {arXiv preprint arXiv:1309.0841},
year = {2013}
}