page_title: Proteus (moon)
section_title: Surface features
hierarchical_section_title: Proteus (moon) / Physical characteristics / Surface features
caption_attribution_description: English: Original caption SHADED RELIEF MAP OF PROTEUS[1] Proteus.gif is a shaded relief map of Proteus, a small inner satellite of Neptune. As with all maps, it is the cartographer's interpretation and not all features are necessarily certain given the limited data available - this interpretation stretches the data as far as is feasible. The original map was published in its full form with latitude-longitude grid and feature names, in: Stooke, P.J., 1994. "The Surfaces of Larissa and Proteus", EARTH, MOON AND PLANETS, V. 65, pp. 31-54. Positions in the map are controlled by a digital shape model, described in that paper. For this map, the three dimensional convex hull of the shape model was projected into the Morphographic Conformal Projection (the conventional Stereographic Projection modified for non-spherical worlds). The leading side (longitude 90 runs vertically down the centre) faces forwards in the orbit of Proteus. The trailing side (longitude 270 runs vertically down its centre) faces backwards along the orbit. Longitude 0 is at the righthand end of the leading side, and faces Neptune. As with all conformal (true shape) projections, the scale in these maps varies, increasing from the centre to the outer edge. The map projection is described in: Stooke, P.J. and Keller, C.P., 1990. "Map Projections for Non-Spherical Worlds / the Variable-Radius Map Projections", CARTOGRAPHICA, V. 27, No. 2, pp. 82-100. This version of the file, with labels intact, is in the public domain. Philip Stooke, Department of Geography, University of Western Ontario, London, Ontario, Canada N6A 5C2 stooke@sscl.uwo.ca
context_page_description: Proteus, also known as Neptune VIII, is the second-largest Neptunian moon, and Neptune's largest inner satellite. Discovered by Voyager 2 spacecraft in 1989, it is named after Proteus, the shape-changing sea god of Greek mythology. Proteus orbits Neptune in a nearly equatorial orbit at the distance of about 4.75 times the radius of Neptune's equator.
  Despite being a predominantly icy body more than 400 km in diameter, Proteus's shape deviates significantly from an ellipsoid. It is shaped more like an irregular polyhedron with several slightly concave facets and relief as high as 20 km. Its surface is dark, neutral in color, and heavily cratered. Proteus's largest crater is Pharos, which is more than 230 km in diameter. There are also a number of scarps, grooves, and valleys related to large craters.
  Proteus is probably not an original body that formed with Neptune. It could have accreted later from the debris formed when the largest Neptunian satellite Triton was captured.
context_section_description: Proteus is heavily cratered, showing no sign of any geological modification. The largest crater, Pharos, has a diameter from 230 to 260 km. Its depth is about 10–15 km. The crater has a central dome on its floor a few kilometres high. Pharos is the only named surface feature on this moon: the name is Greek and refers to the island where Proteus reigned. In addition to Pharos there are several craters 50–100 km in diameter and many more with diameters less than 50 km.
  Other landforms on Proteus include linear features such as scarps, valleys, and grooves. The most prominent one runs parallel to the equator to the west of Pharos. These features likely formed as a result of the giant impacts, which formed Pharos and other large craters or as a result of tidal stresses from Neptune.
caption: Map of Proteus from two sides.
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