The PROSPECT $^{235}$U Antineutrino Spectrum Measurement and its Nuclear Physics Impact

The Precision Reactor Oscillation and SPECTrum experiment, or PROSPECT, detector is designed to accurately measure the $^{235}$U antineutrino energy spectrum. The detector is comprised of 4 tons of Lithium-loaded liquid scintillator with 154 optically separated segments, and achieves excellent pulse-shape discrimination and particle identification. The experiment is located at the High Flux Isotope Reactor (HFIR), an 85 MW$_{Th}$ highly-enriched uranium (HEU) reactor with short reactor-on periods, such that over 99\% of the antineutrino flux comes from $^{235}$U. In this talk, I present the latest spectrum results from PROSPECT and their impact to nuclear physics. We compare the resulting spectrum to model predictions, and test the contribution of $^{235}$U towards potential high energy excess as seen in previous spectrum measurements performed at nuclear power reactors.