• Roth, L.
• Hendrix, A. R.
• Porter, S.
• Parker, J. W.
• Buie, M. W.
• Becker, T. M.
• Molyneux, P. M.

Abstract

The Jupiter Trojan asteroids, located in stable orbits near the Sun-Jupiter L4 and L5 Lagrange points, are hypothesized to have originated in the same trans-Neptunian protoplanetary disk as the Kuiper belt objects, and therefore potentially represent the most readily accessible reserve of primitive outer solar system material. The upcoming NASA Lucy mission will explore this hypothesis, performing five flybys of Jupiter Trojans and characterizing these primordial objects in order to refine theories of the history of the solar system. The final Lucy flyby will target (617) Patroclus and its almost equally sized binary companion, Menoetius. In May 2018 we acquired Hubble Space Telescope observations of (617) Patroclus in the mid-UV spectral region using the Space Telescope Imaging Spectrograph (STIS). By orienting the STIS slit close to 90 degrees from the rotation axis of the system we were able to obtain the first spatially separated spectral observations of Patroclus and Menoetius, rather than a single integrated spectrum. We find that both objects are dark and spectrally flat across the 220 - 315 nm region. We will present our observations of both asteroids and discuss the consistency of the UV data with existing models of Trojan surface composition, which are predominantly based on mixtures of amorphous carbon, graphite, pyrolyzed cellulose and/or tholins, with some potential contribution from amorphous or weathered silicates....

Topics

• surface
• amorphous
• Carbon
• cellulose