Upper Limits on the Escape of Volatiles from (486958) Arrokoth Using New Horizons Alice Ultraviolet Spectrograph Observations

Abstract

During the New Horizons flyby of Kuiper Belt object (486958) Arrokoth on 2019 January 1, a search was made for escaping volatiles. Using the Alice spectrograph, appulse observations of both the Sun and the star HD42954 were performed to look for signatures of far-ultraviolet absorption by various species. No escaping volatiles were detected, and in this article we present upper limits to the escape rates for several species using a Haser model for the maximum line-of-sight column densities that would be undetected at 3σ. These results are useful for models for the formation and evolution of Kuiper Belt objects.