Callisto (moon)
Callisto's anti-Jovian hemisphere imaged in 2001 by NASA's Galileo spacecraft. It shows a heavily cratered terrain. The large impact structure Asgard is on the limb at upper right. The prominent rayed crater below and just right of center is Bran.
|
|||||||||
| Discovery | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Discovered by | Galileo Galilei | ||||||||
| Discovery date | January 7, 1610 | ||||||||
| Designations | |||||||||
| Jupiter IV | |||||||||
| Adjectives | Callistoan, Callistonian | ||||||||
| Orbital characteristics | |||||||||
| Periapsis | 1869000 km | ||||||||
| Apoapsis | 1897000 km | ||||||||
| 1 882 700 km | |||||||||
| Eccentricity | 0.0074 | ||||||||
| 16.6890184 d | |||||||||
|
Average orbital speed
|
8.204 km/s | ||||||||
| Inclination | 2.017° (to the ecliptic) 0.192° (to local Laplace planes) |
||||||||
| Satellite of | Jupiter | ||||||||
| Physical characteristics | |||||||||
|
Mean radius
|
2410.3±1.5 km (0.378 Earths) | ||||||||
| 7.30×107 km2 (0.143 Earths) | |||||||||
| Volume | 5.9×1010 km3 (0.0541 Earths) | ||||||||
| Mass | (1.075938±0.000137)×1023 kg (0.018 Earths) | ||||||||
|
Mean density
|
1.8344±0.0034 g/cm3 | ||||||||
| 1.235 m/s2 (0.126 g) | |||||||||
| 0.359±0.005 (estimate) | |||||||||
| 2.440 km/s | |||||||||
| synchronous | |||||||||
| zero | |||||||||
| Albedo | 0.22 (geometric) | ||||||||
|
|||||||||
| 5.65 (opposition) | |||||||||
| Atmosphere | |||||||||
|
Surface pressure
|
7.5 picobar (7.5×10−10 kPa, 7.4019×10−12 atm) | ||||||||
| Composition by volume | ≈ 4×108 molecules/cm3 carbon dioxide; up to 2×1010 molecules/cm3 molecular oxygen(O2) |
||||||||
Callisto /kəˈlɪstoʊ/ (Jupiter IV) is the second-largest moon of Jupiter, after Ganymede. It is the third-largest moon in the Solar System and the largest object in the Solar System not to be properly differentiated. Callisto was discovered in 1610 by Galileo Galilei. At 4821 km in diameter, Callisto has about 99% the diameter of the planet Mercury but only about a third of its mass. It is the fourth Galilean moon of Jupiter by distance, with an orbital radius of about 1883000 km. It is not in an orbital resonance like the three other Galilean satellites—Io, Europa, and Ganymede—and is thus not appreciably tidally heated. Callisto's rotation is tidally locked to its orbit around Jupiter, so that the same hemisphere always faces inward; Jupiter appears to stand nearly still in Callisto's sky. It is less affected by Jupiter's magnetosphere than the other inner satellites because of its more remote orbit, located just outside Jupiter's main radiation belt.
...
Wikipedia