Near-Infrared Photometry of Mercury

This report summarizes 100 brightness measurements of Mercury made between May 2014 and September 2017 in the J and H near-infrared filters. Brightness models are reported for the J (solar phase angles between 52.3° and 124.5°) and H (solar phase angles between 38.6° and 133.0°) filters. Additional conclusions are as follows: Mercury’s brightness is within 0.1 magnitudes, at a given phase angle, for waxing and waning phases, and the geometric albedos at a solar phase angle of 0° are estimated to be 0.16 ± 0.03 and 0.24 ± 0.05 for the J and H filters, respectively