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New names and insights about Ceres

The Dawn spacecraft is now moving to its third mapping orbit. Nothing new on the bright spots yet, but the crater that contains them has a new name: Occator.

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This pair of images shows color-coded maps from NASA’s Dawn mission, revealing the highs and lows of topography on the surface of dwarf planet Ceres. Image via NASA/JPL-Caltech/UCLA/MPS/DLR/IDA. View larger and read more about this image.

NASA’s Dawn mission to Ceres today (July 28, 2015) released some colorful new maps of the dwarf planet, showcasing a diverse topography, with height differences between crater bottoms and mountain peaks as great as 9 miles (15 km). Dawn is now making its way to its third mapping orbit, and results are coming out of the mission, but still no confirmation on the mysterious bright spots on Ceres. More about that below.

Some of these craters and other features do now have official names, inspired by spirits and deities relating to agriculture from a variety of cultures. The International Astronomical Union recently approved a batch of names for features on Ceres.

The newly labeled features include Occator, the mysterious crater containing Ceres’ brightest spots, which has a diameter of about 60 miles (90 kilometers) and a depth of about 2 miles (4 kilometers).

Occator is the name of the Roman agriculture deity of harrowing, a method of leveling soil.

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Color-coded map from NASA’s Dawn mission shows the highs and lows of topography on the surface of dwarf planet Ceres. Image via NASA/JPL-Caltech/UCLA/MPS/DLR/IDA. View larger and read more about this image

We have been getting regular messages from people along the lines of:

Why hasn’t NASA told us what the bright spots on Ceres are?!

In fact, NASA doesn’t know yet what the bright spots are. That’s why they haven’t told us. The choices include geysers, volcanos, rocks, ice, salt deposits. You can even vote on which option you think is best, here. Marc D. Rayman, who Dawn chief engineer and mission director at JPL, writes the very interesting blog Dawn Journal. He hasn’t been too active in writing blog posts recently (guess he’s busy!), but, in his last entry on June 29, he did point out that the bright spots are only reflecting, not producing, light:

How can you not be mesmerized by the luminous allure of the famous bright spots? They are not, in fact, a source of light, but for a reason that remains elusive, the ground there reflects much more sunlight than elsewhere.

It’s also good to note that there are other bright spots on Ceres. The most noticeable one – the double bright spot that has caused so much speculation – is called Spot 5. The video below shows the other spots pretty well, if you look closely:

One of the bright spots – the spot formerly known as Spot 1 – is now identified as Haulani, after the Hawaiian plant goddess.

The image below shows visible and infrared mapping of Haulani, which has a diameter of about 20 miles (30 km).

Temperature data from Dawn’s visible and infrared mapping spectrometer show that this crater and its bright spot seem to be colder than most of the territory around it.

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This image, from Dawn’s visible and infrared mapping spectrometer (VIR), highlights a bright region on Ceres known as Haulani, named after the Hawaiian plant goddess. Each row shows Ceres’ surface at different wavelengths. Image via NASA/JPL-Caltech/UCLA/MPS/DLR/IDA. View larger and read more about this image.

Dawn is currently spiraling toward its third science orbit, 900 miles (less than 1,500 km) above the surface, or three times closer to Ceres than its previous orbit.

The spacecraft will reach this orbit in mid-August and begin taking images and other data again.

Dawn mission science orbits around dwarf planet Ceres.  Image via NASA Dawn mission.

Dawn mission science orbits around dwarf planet Ceres. Image via NASA Dawn mission.

Bottom line: Features on dwarf planet Ceres now have names. Nothing new on the bright spots yet, but the crater that contains them has been named Occator. Meanwhile, Dawn spacecraft spiraling toward a closer orbit.

Deborah Byrd

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