An outer retrograde satellite of Jupiter, distance 23 942 000 km; also known as Jupiter IX. It orbits Jupiter in 758.9 days at an inclination of 158°.2 to the planet’s equator. Its diameter is 38 km, making it the second-largest member of the Pasiphae irregular group of Jovian satellites. Sinope was discovered in 1914 by the American astronomer Seth Barnes Nicholson (1891–1963).