Abstract

Near-Earth Asteroid 2011 UW158 was observed for 3.5 months with the Hereford Arizona Observatory 0.35-m telescope during the 2015 apparition. A phase curve slope of 0.023 ± 0.001 mag/deg was determined from r'- mag measurements for a phase angle range of 17 to 90 deg. This slope is used to estimate albedo = 0.39 ± 0.09, H = 19.93 ± 0.11, and diameter D = 220 ± 40 m. The UW158 rotation period = 0.61072 h, which is greater than the "spin barrier" of the "rotation frequency vs. diameter" diagram, thus requiring internal cohesion.