HST High-Resolution Images and Maps of Pluto

Abstract

We have obtained Hubble Space Telescope (HST) images of Pluto at 410 and 278 nm which resolve numerous distinct albedo provinces on this planet. Our images were obtained using the Faint Object Camera (FOC) of the Hubble Space Telescope between 1994 June 20 and July 01. This dataset is the first longitudinally-complete, rotationally-resolved direct image dataset on Pluto. We have combined the various images that HST obtained to make maps of the planet. These images reveal that Pluto has (i) a highly variegated surface, (ii) extensive, bright, asymmetric polar regions, (iii) large midlatitude and equatorial spots, and (iv) possible linear features hundreds of kilometers in extent. The dynamic range of albedo features across the planet detected at the FOC's resolution in both the 410 and 278 nm bandpasses exceeds 5:1. We also present and discuss the multiplicative product of the HST 410 and 278 nm maps, which allow us to infer the location of where the cleanest, and therefore the presumably freshest ice deposits, lie. Toward the end of this report, we make some initial comparisons between the HST-derived maps and previously published Pluto maps derived from the inversion of ground-based light curves of Pluto. Although more sophisticated HST map inversions are planned, the data products presented here provide important inputs to modelers interested in volatile transport, and comparative studies of Pluto and Triton.