Ceres is so much more than a drab gray rock drifting among countless others between Mars and Jupiter. Bright spots on its surface were a wonderful surprise for Ceres’ science team and astronomy fans everywhere. This week, NASA is giving us a stunning new look at these bright spots.
The image is in enhanced color, but it’s still breathtaking.
NASA uses enhanced color all the time. It helps pull details out of the image that we might not otherwise see. This image is actually a combination of several. Ceres’ scientists used high-resolution images of the Occator crater captured in February and combined them with color images gathered last September.
The close-up of the bright spots in Occator was just one focused on Ceres’ most prominent crater. Another recent image suggests Occator have seen geologic activity in its recent past. For instance, a dome can now be seen in the smooth-walled pit at the center of Occator crater. Fractures and other features streak across the top and around the dome.
Ralf Jaumann, co-investigator of the Dawn mission, says more mapping of Occator will be needed before scientists know for sure if the crater is home to recent activity.
The enhanced color of Ceres
Just like with the first Occator image, you can see hints of blue across the surface of Ceres.
“Although impact processes dominate the surface geology on Ceres, we have identified specific color variations on the surface indicating material alterations that are due to a complex interaction of the impact process and the subsurface composition,” Jaumann said. “Additionally, this gives evidence for a subsurface layer enriched in ice and volatiles.”
The blue areas highlight parts of Ceres that appear to be very young. This includes mountain and smooth plains.
You’re probably wondering what’s going on with the green and yellow areas. That’s because Dawn’s color imaging coverage is incomplete in those areas.
Haulani crater is different
The composition of Ceres’ subsurface isn’t uniform. Dawn’s visible and infrared mapping spectrometer (VIR) shows Ceres’ surface is made of a mix of materials containing carbonates and phyllosilicates. But Haulani crater shows not all of Ceres’ surface is the same.
“False-color images of Haulani show that material excavated by an impact is different than the general surface composition of Ceres. The diversity of materials implies either that there is a mixed layer underneath, or that the impact itself changed the properties of the materials,” said Maria Cristina de Sanctis, the VIR instrument lead scientist.
The bright material Ceres is best known for is easily seen in the image above. Scientists believe it’s not ice, but some type of salt.
So is Oxo crater
So far, Oxo crater is one of a kind on Ceres. It’s a young crater measuring 6 miles wide. But it stands out as the only crater discovered so far with water, probably in the form of ice.
Dawn will continue to keep a close eye on Oxo crater and elsewhere on Ceres for signs of water.
“Now that we can see Ceres’ enigmatic bright spots, surface minerals and morphology in high resolution, we’re busy working to figure out what processes shaped this unique dwarf planet. By comparing Ceres with Vesta, we’ll glean new insights about the early solar system,” said Carol Raymond, deputy principal investigator for the Dawn mission.
What’s next for Dawn?
Ceres’ visitor just wrapped up a data transfer with Earth and the quest to understanding Ceres continues. With a small change. Dawn is no longer looking straight down at Ceres. Instead, it is pointing its sensors slightly to the left as it circles the rock. Why? Dawn’s team believes this small change could reduce how much hydrazine (fuel) the spacecraft burns through.
How long Dawn orbits Ceres is all about the hydrazine fuel. Without it, Dawn can’t point its instruments at Ceres or its antenna at Earth. When this happens, Dawn won’t crash. Not yet. Dawn’s mission team selected an orbit that would not impact Ceres for at least 50 years. That exceeded the guidelines set by NASA’s Planetary Protection Office of at least 20 years.
We’ll have to wait and see how long this small maneuver change will extend Dawn’s mission. Until then, the spacecraft will continue studying Ceres and answer as many of its mysterious as it can.