Key facts
- Mean diameter
- 4,820.6 km
- Mass
- 1.08 × 10^23 kg (0.0181 Earths)
- Surface gravity
- 1.235 m/s² (0.126 g)
- Escape velocity
- 2.45 km/s
- Mean temperature
- -139 °C
- Rotation period
- 400.56 hours
- Orbital period
- 16.69 days
- Mean distance from Jupiter
- 1.8827 million km
Atmosphere
Negligible or extremely thin.
Composition and structure
Rock and ice.
Discovery and exploration
Its ancient surface records billions of years of impacts.