50th Lunar and Planetary Science Conference 2019 (LPI Contrib. No. 2132) 1723.pdf Discovery of Remarkable Opposition Surges on Pluto and Charon. B. J. Buratti1, M. D. Hicks1, E. Kramer1, J. Bauer2. 1Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109; bon-
[email protected]; 2University of Maryland Department of Astronomy, College Park, MD 20742 Introduction: The July 2015 encounter of the New Observations: Our full request of four nights was Horizons spacecraft with Pluto brought a large Kuiper assigned to this project in 2018 and observations in Belt Object into sharp focus for the first time [1]. Pluto JHK wavelengths (1.2, 1.6 and 2.2 µm) were obtained is a dynamic body with the first-ever active glaciers on all nights. One night was slightly cirussy, and fur- observed outside the Earth, possible clouds, snow, sea- ther data analysis beyond the usual pipeline processing sonal volatile transport, and at least two types of the [2] is required to fully reduce this data. Luckily, this dark, elusive material that is ubiquitous in the outer night was the least critical, being slightly smaller in Solar System and that may be tied to the origin of life solar phase angle than our fourth night, which was ob- on Earth. But as spectacular as this flyby was, it repre- tained at our maximum phase angle. sented an instant in time, leaving out the long temporal baseline that is required to capture, understand, and Table 1-2018 JHK data obtained at opposition model the seasonal events and the types of geologic Time (civil) Solar phase angle (°) Longitude (°) processes that were observed on Pluto – and that hap- July 11 0.008 35 pen on 100-year time scales, at least.