The mystery surrounding the bright spots on the dwarf planet Ceres continues to deepen as NASA's Dawn spacecraft gets closer to this alien world. New photos of Ceres, the largest known object in the asteroid belt, show that the puzzling bright spot that was previously spotted in earlier images is close to another bright albeit dimmer area.
The latest images, which were taken by Dawn on Feb. 19 at proximity of almost 29,000 miles from the dwarf planet, revealed that the bright spot that stood out in earlier images had a neighboring dimmer bright spot and both lie in the same big crater basin.
Andreas Nathues, from the Max Planck Institute for Solar System Research, said that although the bright spots are still currently too small to be resolved by the camera, it is still the brightest object on Ceres. Dawn principal investigator Chris Russell, on the other hand, pointed out that since the two bright spots appear to be in the same basin, this suggests that these spots may have a volcano-like origin.
"Ceres' bright spot can now be seen to have a companion of lesser brightness, but apparently in the same basin," Russell said. "This may be pointing to a volcano-like origin of the spots, but we will have to wait for better resolution before we can make such geologic interpretations."
Cryovolcanoes form on solar systems' cold bodies including the moons that orbit Saturn and Jupiter as well as the dwarf planets in the Kuiper belt. Unlike regular volcanoes found on Earth that eject molten rock though, cryovolcanoes eject liquid water, methane or ammonia when they heat up due to tidal or radioactive processes.
Once they have vented, these cryovolcanoes may leave frozen residues that possibly resemble those that can be seen on the surface of Ceres. Until Dawn gets closer to the dwarf planet, however, any positive identification temporarily remains elusive.
Scientists have long known that regions of higher than average albedo, or reflectiveness, exist on Ceres but planetary scientists have difficulty interpreting what they may be due to low resolution observations.
Dawn is expected to enter Ceres's orbit on March 6. Scientists hope to gather data from its surface that could help them gain a better understanding of its origin and how it evolved. The probe is also hoped to provide a sharper focus of the mysterious bright spots and other features on this extraterrestrial world.