Proteus

Proteus is Neptune's largest moon after Triton.[1] Proteus has an irregular, box-like shape.[1] JPL's physical-parameter table gives Proteus a mean radius of about 208.0 kilometres.[2]

History

Voyager 2 discovered Proteus in 1989.[1]

Findings

Impact scars cover Proteus, with no visible evidence of later geological reshaping.[1] Proteus reflects about six percent of incident sunlight.[1] USGS lists craters among the named feature classes on Proteus.[3]

Current status

Proteus circles Neptune roughly every 27 hours.[1]

Sources

  1. Proteus | NASA Science. Licence: US federal work, public domain (17 USC 105). Attribution: NASA.
  2. Planetary Satellite Physical Parameters | NASA Jet Propulsion Laboratory. Licence: facts-only (Track B), no text reused. Attribution: NASA/JPL-Caltech.
  3. Gazetteer of Planetary Nomenclature: Proteus | USGS. Licence: US federal work, public domain (17 USC 105). Attribution: U.S. Geological Survey.

Evidence as of 2026-11-01.