Discovery of Haze in Pluto’s Atmosphere

Abstract:

The New Horizons spacecraft made the first reconnaissance of the Pluto-Charon system on Jul 14, 2015. The Long Range Reconnaissance Imager (LORRI) on New Horizons obtained images of Pluto and Charon on approach, near closest approach, and on departure. The departure images, obtained at high solar phase angles, unexpectedly revealed that Pluto’s atmosphere is hazy. The haze in Pluto’s atmosphere was detected in each of five images obtained in two separate observations on Jul 14 and on Jul 16, at solar phase angles of 167° and 165° respectively. The haze extends to altitudes of 150 km above Pluto’s surface, with evidence for layering and/or gravity waves. We will present the haze observations and discuss derived physical properties and implications for the atmosphere and its interactions with the surface.