The very detailed images show that the surface of the dwarf planet is a bit more complex than expected.
The new images were made by space probe Dawn. This arrived at Ceres just over a year ago and has gradually reduced the distance to the dwarf planet. At the moment the probe is only 385 kilometers away around Ceres. And from such a small distance the probe can take very detailed photos of the surface. NASA has now released a number of those photos.
In close-up: the Occator crater. Image: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / PSI.
The images that perhaps appeal the most to the imagination show the Occator crater. This crater has kept researchers busy for a long time, because there are somewhat mysterious bright spots in the crater. “Before Dawn Ceres started intensive observation last year, the Occator crater seemed to be one clear area. Now, with the latest images taken at close range, we see complex features that raise new questions, ”says researcher Ralf Jaumann.
The bright spots in the Occator crater in enhanced colors. Image: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / PSI / LPI.
Recent geological activity
The images show that a mountain can be found in the clear heart of the crater. That mountain is surrounded by fractures that run through other, smaller bright spots in the crater. Fractions can also be seen on the top and flanks of the mountain. The whole picture points to "geological activity in the recent past," says Jaumann. Whether this is actually the case will have to be determined from further research.
GRaND detected fewer neutrons in the northern hemisphere. Image: NASA / JPL-Caltech / UCLA / ASI / INAF.
Scientists also come with a new 'card' from Ceres (see above), based on information collected by the GRaND instrument on board Dawn. This instrument studies neutrons and gamma rays caused by the interaction between the surface of Ceres and cosmic radiation and can thus tell more about the composition of that surface (up to a meter deep). Near the poles, the instrument has detected fewer neutrons. It indicates that a lot of hydrogen can be found. Since hydrogen is an important part of water, it is possible that water ice can be found in the polar areas near the surface.
But the top layer of Ceres is not the same everywhere. The Haulani crater, for example, appears to have a completely different composition than its surroundings. It is still unclear why that is. "False color images from Haulani show that the material exposed by an impact is different from the composition of the general surface of Ceres," says researcher Maria Cristina de Sanctis. "The diversity of materials indicates that there is a mixed layer underneath or that the impact itself has changed the properties of the material."
The Haulani crater in fake colors. The image on the left shows differences in brightness. The image in the middle shows differences between the rocks in the crater and beyond. The picture on the right tells more about temperature: blue areas are colder and red areas are warmer. Image: NASA / JPL-Caltech / UCLA / ASI / INAF.
And so, little by little, we learn more about Ceres. "We are excited to be able to reveal these new images, in particular those of Occator that show that complex processes shape the surface of Ceres," says researcher Carol Raymond. “Now that we can see the bright spots, the minerals on the surface and morphology in high resolution, we are busy finding out which processes have shaped this unique dwarf planet. By comparing Ceres with Vesta (a planetoid that Dawn visited earlier, ed.) We gain more insight into the young solar system. ”