Pluto's atmosphere from the 29 June 2015 ground-based stellar occultation at the time of the New Horizons flyby
B. Sicardy, J. Talbot, E. Meza, J. I. B. Camargo, J. Desmars, D., Gault, D. Herald, S. Kerr, H. Pavlov, F. Braga-Ribas, M. Assafin, G., Benedetti-Rossi, A. Dias-Oliveira, A. Ramos-Gomes-Jr., R. Vieira-Martins, D., Berard, P. Kervella, J. Lecacheux, E. Lellouch, W. Beisker

TL;DR
This study reports ground-based stellar occultation observations of Pluto's atmosphere shortly before the New Horizons flyby, revealing an expanding atmosphere with a stable pressure trend and detailed atmospheric structure insights.
Contribution
It provides the first detailed ground-based atmospheric profile of Pluto during the 2015 occultation, offering a valuable comparison to space-based measurements from New Horizons.
Findings
Pluto's atmosphere is still expanding with increased pressure since 2013.
A central flash indicates a spherical, transparent atmospheric layer about 3 km thick.
Estimated surface pressure ranges from 11.9 to 13.7 microbars.
Abstract
We present results from a multi-chord Pluto stellar occultation observed on 29 June 2015 from New Zealand and Australia. This occurred only two weeks before the NASA New Horizons flyby of the Pluto system and serves as a useful comparison between ground-based and space results. We find that Pluto's atmosphere is still expanding, with a significant pressure increase of 52\% since 2013 and a factor of almost three since 1988. This trend rules out, as of today, an atmospheric collapse associated with Pluto's recession from the Sun. A central flash, a rare occurrence, was observed from several sites in New Zealand. The flash shape and amplitude are compatible with a spherical and transparent atmospheric layer of roughly 3~km in thickness whose base lies at about 4~km above Pluto's surface, and where an average thermal gradient of about 5 K~km prevails. We discuss the possibility…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
