Ceres was found to possess bright white spots on its surface when the dwarf planet was first imaged in detail in 2015. The composition of these mysterious regions left astronomers puzzled at first, but a consensus quickly arose that salts were responsible for the large white spots. New analysis suggests this answer may not be entirely correct.
The Occator Crater contains the largest bright spot on the surface of the alien landscape. The region contains the highest concentration of carbonite minerals ever recorded on an extraterrestrial body. The feature stretches 57 miles in length, together with a central pit 6 miles in diameter. This is considered to be a relatively young crater, formed just 80 million years ago.
This new study found this crater is covered in sodium carbonate, a material often found in hydrothermal environments here on Earth. Researchers believe the highly reflective substance was exposed from within Ceres. Such a deposit is inconsistent with material that could have been delivered there through a collision with asteroids.
If this idea is correct, then the interior of Ceres is likely to be significantly warmer than previously believed. Such a scenario could have resulted in the presence of liquid water beneath the surface of the Ceres in the past. This may explain the salts, as the remains of minerals once dissolved in the ancient alien seas.
"The minerals we have found at the Occator central bright area require alteration by water. Carbonates support the idea that Ceres had interior hydrothermal activity, which pushed these materials to the surface within Occator," Maria Cristina De Sanctis, principal investigator of the visible and infrared mapping spectrometer aboard the Dawn spacecraft said.
The instrument utilized by De Sanctis is able to identify materials on the surface of Ceres by studying the wavelengths of sunlight reflected off the bright patches. Ammoniated phyllosilicates were discovered on Ceres in 2015, suggesting the body may have formed closer to the sun and traveled outward in the past. New analysis reveals the presence of salts containing ammonia within the bright patches. Similar eruptions have been seen in volcanic eruptions on the surface of Enceladus, a moon orbiting Saturn.
Analysis of the data from Dawn shows that craters on Ceres are often more than a mile or two deeper than surrounding regions. This suggests that erosion has played little role in the evolution of these craters, even over the course of billions of years. These calculations suggest that the interior of Ceres could not contain more than 40 percent ice by volume, with the remainder consisting of rocks, salts and other constituents.