 The ellipsoid dimensions of kilometers – corresponding to a mean-diameter of 132.5 kilometers, equivalent to the volume of a sphere – were estimated using follow-up photometry at Ondřejov Observatory and Mitaka Observatory that determined the body's rotational phase at the exact time of the occultation event.This minor planet was named from Greek mythology after the hero Diomedes, King of Argos and known for his participation in the Trojan War, regarded as the best warriors of the Achaeans, just behind Achilles and alongside with Ajax.The official naming citation was mentioned in "The Names of the Minor Planets" by Paul Herget in 1955 ().