 Between 2003 and 2017, several additional lightcurves were obtained by American photometrists Robert Stephens and Brian Warner at the Santana Observatory (), the Palmer Divide Observatory () and the Palmer Divide Station (), respectively.The constructed lightcurve gave a shorter period for "Riema" between 3.566 and 3.588 hours with a low amplitude of 0.06 to 0.19 magnitude ().According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, "Riema" measures 4.605 kilometers in diameter and its surface has an outstandingly high albedo of 1.000.