It orbits the Sun in the outer main-belt at a distance of 3.2–3.5 AU once every 6 years and 2 months (2,238 days).
Lightcurve analysis gave a rotation period of 30.51 hours with a brightness amplitude of 0.10 magnitude, indicative for a spheroidal shape (U=3-/3-).
[10][11][a] Previous observations by Brian Warner gave a longer period of 82 hours based on sparse photometry (U=2-).
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, Gonnessia measures between 91.98 and 104.63 kilometers in diameter and its surface has an albedo between 0.03 and 0.040.
[4][5][6][7] The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is an albedo of 0.0398 with a diameter of 91.98 kilometers.