New maps from NASA’s Dawn spacecraft reveal more about both the landscape and composition of the largest asteroid.

Dawn team members presented new maps of the dwarf planet Ceres today at the European Planetary Science Conference in Nantes, France. We’re still not at the point where we’re taking snazzy spectra of the surface — so no word yet on what those bumfuzzling bright spots are made of. But one of the released false-color maps does show how the surface’s composition changes across the asteroid, so we’re getting closer. Literally: in October, Dawn will begin descending to its lowest orbit around the asteroid, which is when it’ll take those long-awaited spectral measurements.

composition of Ceres' surface
The Dawn spacecraft took the images combined in this map-projection view of Ceres during its high-altitude mapping orbit, in August and September 2015. The composite combines images taken using infrared, red, and blue spectral filters. These subtle color differences would appear fairly uniform in natural color. Enhancing them in this false-color way can provide valuable insights into the mineral composition of the surface, as well as the relative ages of surface features. Click to zoom or see this link.
NASA / JPL-Caltech / UCLA / MPS / DLR / IDA

The team determined how the surface’s makeup changes by taking images through different filters: infrared (920 nanometers), red (750 nm), and blue (440 nm). A feature appears brightest at the wavelength at which it reflects the most light; the reddest places are those that strongly reflect infrared light. Green marks the happy medium locations, where features are very reflective at all wavelengths — in science speak, the albedo is high. One of those locations is, naturally, the bright spots in the crater Occator. That crater is the divot carved out of the big blue region to the map's center right.

Ceres topographic map from high-altitude orbit
This color-coded map shows the topographic highs and lows on the surface of the dwarf planet Ceres. The color scale extends about 7.5 kilometers (5 miles) above and below reference surfaces. Occator Crater, the home of the mysterious bright spots, sits in a highlands region center right in the image. Not pictured is Kait Crater, which lies on longitude 0.
NASA / JPL-Caltech / UCLA / MPS / DLR / IDA

As you can see from the topographic map at right, the crater Occator lies in a highlands region and doesn’t dig as deep into the surface as other craters. What does that mean? For now, not a clue. (Bring on those spectra!) The map also has some new and approved feature names, such as the 20-kilometer-wide (12-mile-wide) Ysolo Mons near Ceres’ north pole. Ceres’ nomenclature falls into the category of agriculture-related spirits, deities, and festivals from cultures around the world, in keeping with the fact that Ceres was the Roman goddess of agriculture, grain, and (depending on the source you read) motherly love.


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Image of Robert-Casey


September 30, 2015 at 12:11 pm

Looking forward to seeing some true color hi-res pictures of Ceres (like that low resolution pix from the Hubble telescope). So far, all I've seen are black and whites, which makes Ceres, aside from the bright spots, look like a boring ball of craters.

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Image of Anthony Barreiro

Anthony Barreiro

September 30, 2015 at 7:20 pm

On the topographic map, red seems to depict higher elevations and blue lower elevations. Is this correct?

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Image of

October 2, 2015 at 4:30 pm

That's correct. Fascinating to overlay the topo and false-color maps and see a glimpse into how mineral composition varies with surface features.

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