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Dawn found Ceres's surface to be a mixture of water ice and hydrated minerals such as carbonates and clay. Gravity data suggest Ceres to be partially differentiated into a muddy (ice-rock) mantle/core and a less dense but stronger crust that is at most thirty per cent ice by volume.
Ceres' shape is controlled mainly by gravity and spin, with only a 3% departure from hydrostatic equilibrium. Its best-fit shape is a triaxial ellipsoid with dimensions a = 483.1 km, b = 481.0, km and c = 445.9 km, with c being the north-south axis and a and b the semimajor and semiminor equatorial axes.
However, Ceres (r = 470 km) is the smallest body for which detailed measurements are consistent with hydrostatic equilibrium, [8] ... Surface area Density Gravity ...
Since 2008, there have been five dwarf planets recognized by the IAU, although only Pluto has actually been confirmed to be in hydrostatic equilibrium [25] (Ceres is close to equilibrium, though some anomalies remain unexplained). [26] Ceres orbits in the asteroid belt, between Mars and Jupiter. The others all orbit beyond Neptune.
The surface gravity, g, of an astronomical object is the gravitational acceleration experienced at its surface at the equator, including the effects of rotation. The surface gravity may be thought of as the acceleration due to gravity experienced by a hypothetical test particle which is very close to the object's surface and which, in order not to disturb the system, has negligible mass.
Months ago, NASA's Dawn spacecraft began capturing images of Ceres, and among the many intriguing surface features it has discovered is a rather mysterious conical mountain. The agency announced ...
Ceres is saturated with impact craters.Many have a central pit or bright spot. In the first batch of 17 names approved by the IAU, craters north of 20° north latitude had names beginning with A–G (with Asari being the furthest north), those between 20° north and south latitude beginning with H–R, and those further south beginning with S–Z (with Zadeni being the furthest south).
There are indications that Ceres may have a tenuous atmosphere and water frost on the surface. Surface water ice is unstable at distances less than 5 AU from the Sun, so it is expected to vaporize if it is exposed directly to solar radiation. Water ice can migrate from the deep layers of Ceres to the surface, but escapes in a very short time.