In addition to the strange bright spots in a large crater on Ceres, there are also odd bright streaks down the sides of a pyramid-shaped mountain which rises higher than Alaska’s 20,000-foot Mt. McKinley, NASA shows in the latest video from the Dawn mission.
Dawn science team member Paul Schenk, a geologist at the Lunar and Planetary Institute, said:
“This mountain is among the tallest features we’ve seen on Ceres to date. It’s unusual that it’s not associated with a crater. Why is it sitting in the middle of nowhere? We don’t know yet, but we may find out with closer observations.”
Another puzzle is the infamous Occator crater, home to Occator’ brightest spots.
A new animation simulates a close flyover of this area.
The crater takes its name from the Roman agriculture deity of harrowing, a method of pulverizing and smoothing soil. In investigating the way Occator’s bright spots reflect light at different wavelengths, the Dawn science team has not found evidence that is consistent with ice.
The spots’ albedo, a measure of the amount of light reflected, is also lower than predictions for concentrations of ice at the surface. Chris Russell, Dawn’s principal investigator at the University of California, Los Angeles, said:
“The science team is continuing to evaluate the data and discuss theories about these bright spots at Occator. We are now comparing the spots with the reflective properties of salt, but we are still puzzled by their source. We look forward to new, higher-resolution data from the mission’s next orbital phase.”
Dawn is to resume its Ceres observations in mid-August, from an altitude of 900 miles, or three times closer to Ceres than its previous orbit.
Ceres is the largest object in the main asteroid belt between Mars and Jupiter. Thanks to data acquired by Dawn since the spacecraft arrived in orbit at Ceres, scientists have revised their original estimate of Ceres’ average diameter to 584 miles. The previous estimate was 590 miles.
Photo: The intriguing brightest spots on Ceres lie in a crater named Occator, which is about 60 miles (90 kilometers) across and 2 miles (4 kilometers) deep. This image comes from an animation, generated using data from NASA’s Dawn spacecraft. Vertical relief has been exaggerated by a factor of five. Exaggerating the relief helps scientists understand and visualize the topography much more easily, and highlights features that are sometimes subtle. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/LPI