Cruise Over Ceres

A prominent mountain with bright streaks on its steep slopes is especially fascinating to scientists. The peak’s shape has been likened to a cone or a pyramid. It appears to be about 4 miles (6 kilometers) high, with respect to the surface around it, according to the latest estimates. This means the mountain has about the same elevation as Mount McKinley in Denali National Park, Alaska, the highest point in North America.

Rethinking Ceres’s Physical Properties

Dawn’s images show that Ceres is a slightly ellipsoidal body measuring 965 by 891 km (600 by 554 miles). That’s smaller than we’d assumed, but not by much — so its overall density must be 2.16 g/cm3, about 4% higher than previous estimates. This increases the assumed percentage of water in the dwarf planet. “Ceres is a prototype wet protoplanet, intact from the earliest days of the solar system,” Russell concludes.

This artist concept shows NASA’s Dawn spacecraft above dwarf planet Ceres, as seen in images from the mission. Source: Sky & Telescope

Ceres Topographic Globe Animation

This animation shows a color-coded map from NASA’s Dawn mission revealing the highs and lows of topography on the surface of dwarf planet Ceres.

The color scale extends 3.7 miles (6 kilometers) below the surface in purple to 3.7 miles (6 kilometers) above the surface in brown. The brightest features (those appearing nearly white) – including the well-known bright spots within a crater in the northern hemisphere – are simply reflective areas, and do not represent elevation. The topographic map was constructed from analyzing images from Dawn’s framing camera taken from varying sun and viewing angles. The map was combined with an image mosaic of Ceres and projected onto a 3-D shape model of the dwarf planet to create the animation. 

Source: NASA

This artist’s concept shows NASA’s Dawn spacecraft arriving at the dwarf planet Ceres, the most massive body in the asteroid belt. Dawn is the first mission to visit a dwarf planet – a round body that orbits the sun but, unlike a planet, does not clear its orbital path of other objects.

Ceres Bright Spots Seen Closer Than Ever

NASA’s Dawn mission captured a sequence of images, taken for navigation purposes, of dwarf planet Ceres on May 16, 2015. The image showcases the group of the brightest spots on Ceres, which continue to mystify scientists. It was taken from a distance of 4,500 miles (7,200 kilometers) and has a resolution of 2,250 feet (700 meters) per pixel. 

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Dawn’s voyage milestones

Illustration of the relative locations (but not sizes) of Earth, the sun, Dawn and Ceres on April 12, 2015. (Earth and the sun are at that location every April 12.) The distance from Earth to Dawn is the same as the distance from the sun to Dawn. The images are superimposed on the trajectory for the entire mission, showing the positions of Earth, Mars, Vesta, and Ceres at milestones during Dawn’s voyage.

Dawn’s four mapping orbits

Each orbit is designed to provide a better view than the one before, and Dawn will map the orb thoroughly while at each altitude. The names for the orbits – rotation characterization 3 (RC3); survey; high altitude mapping orbit (HAMO); and low altitude mapping orbit (LAMO) – are based on ancient ideas, and the origins are (or should be) lost in the mists of time. Readers should avoid trying to infer anything at all meaningful in the designations. After some careful consideration, your correspondent chose to use the same names the Dawn team uses rather than create more helpful descriptors for the purposes of these blogs. That ensures consistency with other Dawn project communications. After all, what is important is not what the different orbits are called but rather what amazing new discoveries each one enables.

Dawn RC3 Image 10

This image of Ceres is part of a sequence taken by NASA’s Dawn spacecraft on May 4, 2015, from a distance of 8,400 miles (13,600 kilometers).

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Dawn RC3 Image 9

This image of Ceres is part of a sequence taken by NASA’s Dawn spacecraft on May 4, 2015, from a distance of 8,400 miles (13,600 kilometers).

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA 

The bright spots on Ceres

This image is part of a sequence of images taken by NASA’s Dawn spacecraft on May 4, 2015, from a distance of 8,400 miles (13,600 kilometers), in its RC3 mapping orbit. The image resolution is 0.8 mile (1.3 kilometers) per pixel. 

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

In this closest-yet view, the brightest spots within a crater in the northern hemisphere are revealed to be composed of many smaller spots. However, their exact nature remains unknown.

Ceres from a distance of 13,600 km

This image of Ceres is part of a sequence taken by NASA’s Dawn spacecraft on May 4, 2015, from a distance of 8,400 miles (13,600 kilometers). 

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Dawn mission at Vesta and Ceres

nasa.gov

The asteroid Vesta and the recently categorized dwarf planet Ceres have been selected because, while both speak to conditions and processes early in the formation of the solar system, they developed into two different kinds of bodies. Vesta is a dry, differentiated object with a surface that shows signs of resurfacing. It resembles the rocky bodies of the inner solar system, including Earth. Ceres, by contrast, has a primitive surface containing water-bearing minerals, and may possess a weak atmosphere. It appears to have many similarities to the large icy moons of the outer solar system.

By studying both these two distinct bodies with the same complement of instruments on the same spacecraft, the Dawn mission hopes to compare the different evolutionary path each took as well as create a picture of the early solar system overall. Data returned from the Dawn spacecraft could provide opportunities for significant breakthroughs in our knowledge of how the solar system formed.