 In March 2010, astronomer Robert Stephens obtained another lightcurve at the Center for Solar System Studies, that gave a divergent period of 11.989 hours with an amplitude of 0.40 magnitude ().According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, "Irmela" measures between 17.00 and 20.683 kilometers in diameter and its surface has an albedo between 0.0503 and 0.105.10µm radiometric data collected from Kitt Peak National Observatory in 1975, gave a diameter estimate of 19 kilometers.