Reference image
Object guide
Proteus is one of Neptune's larger inner moons; it has an irregular shape and heavily cratered surface. Proteus is approximately 420 km across.
How to observe Proteus
Proteus is resolved as a separate world mainly through imaging or spacecraft data; visually, its relationship to neptune is the key observing context.
Scientific context
Useful scale comparisons are 0.033 Earth diameters, 0.006 g surface gravity, 0.003 Earth years per orbit. These values are rounded from the catalogue measurements shown on this page.
- Radius
- 210 km
- Diameter
- 420 km
- Mass
- 5,000,000,000,000,000,000 kg
- Mean density
- 0.129 g/cm³
- Surface gravity
- 0.06 m/s² (0.006 g)
- Orbital period
- 1.122 days (0.003 years)
- Parent body
- neptune
0.033 Earth diameters0.006 g surface gravity0.003 Earth years per orbit
Source: NASA Science (checked 2026-08-09). Values are rounded catalogue measurements.
Interactive orbit model
Aug 13, 2026, 22:251×
Calculated positions / separate exploration scales