Several trace constituents can reach saturation vapor pressure in Pluto's present day atmosphere. As such, we describe a search for discrete could features in Pluto's atmosphere using New Horizons data obtained on 14-15 July 2015, during the Pluto flyby closest approach. We report that Pluto's present day atmosphere is at least largely (>99% by surface area) free of discrete clouds. We also report a handful of features that may plausibly be clouds, all of which were detected obliquely and at high phase observing geometry. No cloud candidates were identified away from the terminators or in low phase (backscattering geometry) images.
@article{arxiv.1706.03389,
title = {Evidence for Possible Clouds in Pluto's Present Day Atmosphere},
author = {S. A. Stern and J. A. Kammer and E. L. Barth and K. N. Singer and T. R. Lauer and J. D. Hofgartner and H. A. Weaver and K. Ennico and C. B. Olkin and L. A. Young and the New Horizons LORRI Instrument Team and the New Horizons Ralph Instrument Team and the New Horizons Atmospheres Investigation Team},
journal= {arXiv preprint arXiv:1706.03389},
year = {2017}
}
Comments
18 pages, 7 figures, 3 tables, The Astronomical Journal, 2017, in press