2.3.1 spase://CNES/NumericalData/CDPP-AMDA/Ephemerides/io-orb-all Io 2018-10-14T11:46:29Z Io orbits Jupiter at a distance of 421,700 km from Jupiter's center and 350,000 km from its cloudtops. It is the innermost of the Galilean satellites of Jupiter, its orbit lying between those of Thebe and Europa. Including Jupiter's inner satellites, Io is the fifth moon out from Jupiter. It takes Io about 42.5 hours to complete one orbit around Jupiter. Io is in a 2:1 mean-motion orbital resonance with Europa and a 4:1 mean-motion orbital resonance with Ganymede, completing two orbits of Jupiter for every one orbit completed by Europa, and four orbits for every one completed by Ganymede. This resonance helps maintain Io's orbital eccentricity (0.0041), which in turn provides the primary heating source for its geologic activity. Without this forced eccentricity, Io's orbit would circularize through tidal dissipation, leading to a geologically less active world. Like the other Galilean satellites and the Moon, Io rotates synchronously with its orbital period, keeping one face nearly pointed toward Jupiter. This synchronicity provides the definition for Io's longitude system. Io's prime meridian intersects the equator at the sub-Jovian point. The side of Io that always faces Jupiter is known as the subjovian hemisphere, whereas the side that always faces away is known as the antijovian hemisphere. The side of Io that always faces in the direction that Io travels in its orbit is known as the leading hemisphere, whereas the side that always faces in the opposite direction is known as the trailing hemisphere. spase://CNES/Person/NAIF PrincipalInvestigator jup-moons-orb PartOf Jupiter Moons spase://SMWG/Repository/CNES/CDPP-AMDA Online Open http://amda.cdpp.eu Text.ASCII SPICE spase://CNES/Instrument/CDPP-AMDA/Ephemerides Ephemeris 1970-01-01T00:00:05Z 2036-12-31T23:40:04Z PT20M Jupiter Jupiter.Io distance io-jupiter io_jup_r Rj TimeSeries Positional xyz_jsm io_jup_jsm Rj Cartesian JSM TimeSeries 3 x 1 io_jup_jsm(0) y 2 io_jup_jsm(1) z 3 io_jup_jsm(2) Positional xyz_jso io_jup_jso Rj Cartesian JSO TimeSeries 3 x 1 io_sat_jso(0) y 2 io_jup_jso(1) z 3 io_jup_jso(2) Positional xyz_IAU_jupiter io_jup_xyz Rj Cartesian IAU_Jupiter TimeSeries 3 x 1 io_jup_xyz(0) y 2 io_jup_xyz(1) z 3 io_jup_xyz(2) Positional latitude IAU_jupiter io_jup_lat deg Positional longitude IAU_jupiter io_jup_lon deg Positional