Sinope did not receive its present name until 1975;[10][11] before then, it was simply known as Jupiter IX. It was sometimes called "Hades"[12] between 1955 and 1975.
Sinope orbits Jupiter on a high-eccentricity and high-inclination retrograde orbit. Its orbit is continuously changing due to solar and planetary perturbations.[13] Sinope is believed to belong to the Pasiphae group of retrograde irregular moons.[14] However, given its mean inclination and different colour, Sinope could be also an independent object, captured independently, unrelated to the collision and break-up at the origin of the group.[15] The diagram illustrates Sinope's orbital elements in relation to other satellites of the group.
Sinope is also known to be in a secular resonance with Jupiter, similar to Pasiphae. However, Sinope can drop out of this resonance and has periods of both resonant and non-resonant behaviour in time scales of 107 years.[16]
From measurements of its thermal emission, Sinope has an estimated diameter of 35 km (22 mi).[7] Sinope is red (colour indices B−V=0.84, R−V=0.46),[15] unlike Pasiphae, which is grey.
Sinope's infraredspectrum is similar to those of D-type asteroids but different from that of Pasiphae.[17] These dissimilarities of the physical parameters suggest a different origin from the core members of the group.
^Sheppard, Scott. "Scott S. Sheppard - Jupiter Moons". Department of Terrestrial Magnetism. Carnegie Institution for Science. Retrieved 26 November 2020.