NASA's Dawn spacecraft spots pyramid-shaped peak on Ceres

WASHINGTON: NASA's Dawn spacecraft has captured more images of mysterious bright spots on Ceres, and also spotted a baffling pyramid-shaped peak towering over a relatively flat landscape on the dwarf planet.

The latest images of Ceres from NASA's Dawn spacecraft show a mountain with steep slopes protruding from a relatively smooth area of the dwarf planet's surface. The structure rises about 5 kilometres above the surface.

"The surface of Ceres has revealed many interesting and unique features. For example, icy moons in the outer solar system have craters with central pits, but on Ceres central pits in large craters are much more common," said Carol Raymond, deputy principal investigator for the Dawn mission, based at NASA's Jet Propulsion Laboratory in Pasadena, California.

"These and other features will allow us to understand the inner structure of Ceres that we cannot sense directly," Raymond said.

Dawn has been studying the dwarf planet in detail from its second mapping orbit, which is 4,400 kilometres above Ceres.

A new view of its intriguing bright spots, located in a crater about 90 kilometres across, shows even more small spots in the crater than were previously visible, NASA said.

At least eight spots can be seen next to the largest bright area, which scientists think is approximately 9 kilometres wide.

A highly reflective material is responsible for these spots - ice and salt are leading possibilities, but scientists are considering other options, too.

Dawn's visible and infrared mapping spectrometer allows scientists to identify specific minerals present on Ceres by looking at how light is reflected.

Each mineral reflects the range of visible and infrared-light wavelengths in a unique way, and this signature helps scientists determine the components of Ceres.

So, as the spacecraft continues to send back more images and data, scientists will learn more about the mystery bright spots.

Ceres also has numerous craters of varying sizes, many of which have central peaks. There is ample evidence of past activity on the surface, including flows, landslides and collapsed structures.

It seems that Ceres shows more remnants of activity than the protoplanet Vesta, which Dawn studied intensively for 14 months in 2011 and 2012, researchers said.

Dawn is the first mission to visit a dwarf planet, and the first to orbit two distinct targets in our solar system. It arrived at Ceres, the largest object in the main asteroid belt between Mars and Jupiter, on March 6, 2015.

Dawn will remain in its current altitude until June 30, continuing to take images and spectra of Ceres in orbits of about three days each. It then will move into its next orbit at an altitude of 1,450 kilometres, arriving in early August.