Presentation #102.06 in the session “Pluto System: Atmosphere”.
We present a joint retrieval of Pluto’s haze morphology in the lower 50 km above its surface, using observations from multiple instruments onboard the New Horizons spacecraft. Haze in Pluto’s atmosphere is one of the most distinctive features seen during New Horizons’ historic flyby in 2015. The haze was directly imaged at visible and near infrared wavelengths by the Long Range Reconnaissance Imager (LORRI), the Multispectral Visible Imaging Camera (MVIC), the Linear Etalon Imaging Spectral Array (LEISA), and investigated in the ultraviolet (UV) by the Alice spectrograph using solar occultations. Cheng et al. (2017) showed, using simplified models, that neither spherical nor two-dimensional aggregate particles could satisfy the set of all observations. Contradictory conclusions have been drawn from observations of different instruments. Both forward and backward scattering are large compared to a given extinction. Here, we present retrieval results of a bimodal distribution of haze particles, which consists of a small population of ~80 nm and a large population near ~1 μm. This result successfully addresses the disagreement among the instruments, and provides important constraints on local haze production and gas condensation in Pluto’s atmosphere.