[3] In 2002, 2007 and 2017, three rotational light curves of Leonce were obtained from photometric observations by amateur astronomers René Roy, Laurent Bernasconi and Daniel Klinglesmith and colleagues at Etscorn Observatory (719), respectively.

Analysis gave a well-defined light curve with a consolidated rotation period of 4.3250 hours and a brightness amplitude between 0.49 and 0.63 magnitude (U=3/3/3).

[3][11][12] In addition a modeled light curve, using photometric data from various sources, gave a period of 4.32527 hours, as well as two spin axes of (210.0°, −67.0°) and (46.0°, −77.0°) in ecliptic coordinates.

[13] According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Leonce measures between 14.94 and 22.456 kilometers in diameter and its surface has an albedo between 0.0348 and 0.10.

[5][6][7][8][9][10] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0706 and a diameter of 18.16 kilometers based on an absolute magnitude of 12.2.