  The recently launched Lucy mission aims to understand the dynamical history
of the Solar System by examining the Jupiter Trojans, a population of primitive
asteroids co-orbital with Jupiter. Using the G280 grism on the Hubble Space
Telescope's Wide Field Camera 3 we obtained near ultraviolet spectra of four of
the five Lucy mission targets -- (617) Patroclus-Menoetius, (11351) Leucus,
(3548) Eurybates, and (21900) Orus -- to search for novel spectral features. We
observe a local reflectance minimum at 0.4 $\mu$m accompanied by an increase in
reflectance from 0.35-0.3 $\mu$m in the spectra of Patroclus and Orus. We use
the principles of Rayleigh scattering and geometric optics to develop a Hapke
optical model to investigate whether this feature can be explained by the
presence of submicroscopic grains on Trojan surfaces. The near ultraviolet
"bump" feature can be explained by scattering due to fine-grained opaques
(iron, amorphous carbon, or graphite) with grain sizes ranging from 20 - 80 nm.
