|Discovered by||S. B. Nicholson|
|Discovery date||July 21, 1914|
Mean orbit radius
|724.1 d (1.95 a)|
Average orbital speed
|Inclination||128.11° (to the ecliptic)|
153.12° (to Jupiter's equator)
|2.6 g/cm3 (assumed)|
|0.014 m/s2 (0.001 g)|
Sinope (// si-NOH-pee; Greek: Σινώπη) is a retrograde irregular satellite of Jupiter discovered by Seth Barnes Nicholson at Lick Observatory in 1914, and is named after Sinope of Greek mythology.
Sinope orbits Jupiter on a high-eccentricity and high-inclination retrograde orbit. The orbital elements are as of January 2000. They are continuously changing due to solar and planetary perturbations. It is often believed to belong to the Pasiphae group. 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. 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.
Sinope's infrared spectrum is similar to those of D-type asteroids but different from that of Pasiphae. These dissimilarities of the physical parameters suggest a different origin from the core members of the group.