Cressida belongs to the Portia group of satellites, which includesBianca,Desdemona,Juliet,Portia,Rosalind,Cupid,Belinda, andPerdita.[7] These satellites have similar orbits and photometric properties.[7] Other than its orbit,[3] size of 92 km × 74 km (57 mi × 46 mi),[4] and geometric albedo of 0.08,[7] little is known about it.
InVoyager 2 imagery Cressida appears as an elongated object, with its major axis pointing towards Uranus. The ratio of axes of Cressida's prolate spheroid is 0.8 ± 0.3.[4] Its surface is grey in color.[4]
Cressida orbits close to a 3:2resonance with the η ring, one of therings of Uranus. Perturbations of the ring's shape provide a way to measure the mass of Cressida, which in 2024 was found to be(1.839±0.212)×1017 kg.[5] Cressida is one of the few small satellites of Uranus for which the mass has been directly measured.[5][6]
Cressida may collide withDesdemona within the next 100 million years.[11]
