Evidence from Voyager II photometry for early resurfacing of Umbriel

  title={Evidence from Voyager II photometry for early resurfacing of Umbriel},
  author={P. Helfenstein and Peter C. Thomas and Joseph Frank Veverka},
THE uranian satellite UmbriePs dark, heavily cratered surface is remarkable for its apparent uniformity in Voyager II images1. Its most conspicuous geological feature is a comparatively high-albedo, annulus-shaped deposit which covers the floor of the 40-km diameter crater Wunda1. Here we present new Voyager II albedo maps of Umbriel which reveal that its surface is subdivided into low-contrast, crudely polygonal areas ranging in size from tens to hundreds of kilometres (Fig. 1). The largest… 

Topography and geology of Uranian mid-sized icy satellites in comparison with Saturnian and Plutonian satellites

Newly processed global imaging and topographic mapping of Uranus's five major satellites reveal differences and similarities to mid-sized satellites at Saturn and Pluto. Three modes of internal heat

Surface modification of icy satellites: Space weathering of the large moons of Uranus and alluvial fan formation on Saturn’s moon Titan

The surfaces of the large Uranian satellites are characterized by a mixture of H2O ice and a dark, potentially carbon-rich, constituent, along with CO2 ice. At the mean heliocentric distance of the

Planetary structural mapping

Summary As on Earth, other solid-surfaced planetary bodies in the solar system display landforms produced by tectonic activity, such as faults, folds, and fractures. These features are resolved in



Voyager 2 in the Uranian System: Imaging Science Results

Voyager 2 images of the southern hemisphere of Uranus indicate that submicrometersize haze particles and particles of a methane condensation cloud produce faint patterns in the atmosphere, and Voyager images confirm the extremely low albedo of the ring particles.

Bidirectional reflectance spectroscopy: 1. Theory

  • B. Hapke
  • Physics, Environmental Science
  • 1981
An approximate analytic solution to the radiative transfer equation describing the scattering of light from particulate surfaces is derived. Multiple scattering and mutual shadowing are taken into