New Horizons LORRI Pluto Haze Spatial Analysis

Abstract:

We present analysis results from the New Horizons (NH) Pluto atmosphere haze measurements. Observations were taken by the LORRI clear filter narrow angle camera [1] during the NH Pluto close flyby on 14 July 2014. Both high phase angle (forward scattering) look back and low phase angle (back scattering) sunlit hemisphere observations were obtained. The haze is clearly detected in the forward scattered images, but systematics due to scattered light contributions from Pluto’s surface must be accounted for in order to accurately determine any azimuthal or latitudinal dependence. The haze extends at least 150 km above the surface of Pluto, and could contain layer structures as well. In the backscattered images, the haze is dominated by backscattered light from Pluto’s surface in the lossy images currently on the ground. In this paper we report on the latest LORRI haze spatial distribution analysis results and their implications.

¹Cheng, A.F. et al. 2008, Space Science Reviews, Volume 140, Issue 1-4, pp. 189-215

Figure 1: LORRI lookback image of Pluto taken on 16 Jul 2015 03:40 UT. This moderate resolution (9.8 km/pix) image is lossless and shows the full extent of Pluto's disk. The haze can clearly be seen extending more than 10% of a Pluto radii above the solid surface of the planet. Potential structures in the haze seen in this image will be discussed.