What processes influenced the gradient in material seen today from the dry rocky bodies of the inner solar system through the asteroid belt to the water and volatile-rich outer solar system?
Dawn at Ceres – starship enterprise smooth craters. Just finished the first science orbit at 13500 km, watched Ceres rotate beneath the spacecraft
Big relaxed basin.
Polygonal craters – light/dark regions, smooth and rough terrains
Dawn mapped in great detail the geology and the minerals on the surface, found a diversity of materials, and giant tectonic cracks caused by giant impacts. Big impacts – more meteorites than any other body – intact building block protoplanet
Colors indicate concentration of H – 4x expected – indicates water from exogenic material – same as delivery of water to inner planets
Bright spots – very bright, not yet resolved at 2 km/px as bright as salts or ice. Together with the cratering record on the surface and the overall surface morphology, it appears that Ceres has a layer of ice mixed with rock and salts. This is important because it suggests that the rock interacted with the past liquid ocean and there was circulation of material via convection, between the ocean floor and the surface
Comets/asteroids in continuous spectrum – delivered water to earth and inner planets
Astronauts and Robots 2015: JPL
At the dawn of the solar system the solar nebula was rich in radioactive
heat sources, a portion of which decayed rapidly within the first few
– Were there chemical variations in the nebular disk?
– How did the formation time affect the outcome?
– What processes have mixed material post-formation?
Vesta Size in Context
Ceres and Vesta Size in
Dawn at Ceres
Survey Orbit: 4400 km alt. Jun 5 –Jul 1 2015
HAMO: 1470 km alt. Aug 4 – Oct 8 2015
LAMO: 375 km alt. Dec 1 2015 – Mar 6 2016
HAMO: High Altitude Mapping Orbit LAMO: Low Altitude Mapping Orbit