A research group from the Southwest Research Institute has discovered evidence that the surface of the dwarf planet Ceres is filled with carbon matter.
Using data from NASA’s Dawn spacecraft, the researchers concluded that the planet’s surface likely contains a concentration of carbon that is several times more than what is present in the most carbon-rich, primitive meteorites found on Earth.
“Ceres is like a chemical factory,” SwRI’s Simone Marchi, PhD, a principal scientist who was the lead author of the study, said in a statement. “Among inner solar system bodies, Ceres’ has a unique mineralogy, which appears to contain up to 20 percent carbon by mass in its near surface.
“Our analysis shows that carbon-rich compounds are intimately mixed with products of rock-water interactions, such as clays,” he added.
Astronomers believe that Ceres originated approximately 4.6 billion years ago at the dawn of our solar system. Along with the newly discovered carbon presence, previous data revealed that the planet includes the presence of water and other volatiles like ammonium derived from ammonia, suggesting that Ceres formed in a cold environment, possibly outside of the orbit of Jupiter.
One theory is that a shakeup in the orbits of larger planets pushed Ceres to its current home in the main asteroid belt between the orbits of Mars and Jupiter.
“With these findings, Ceres has gained a pivotal role in assessing the origin, evolution and distribution of organic species across the inner solar system,” Marchi said. “One has to wonder about how this world may have driven organic chemistry pathways, and how these processes may have affected the make-up of larger planets like the Earth.”
The team examined geophysical, compositional and collisional models of Ceres based on the new Dawn data and found that fluid processes have altered the planet’s partially differentiated interior.
Dawn’s Visible and Infrared Mapping Spectrometer has shown that the overall low albedo of Ceres surface is a combination of rock-water interaction products like phyllosilicates and carbonates and a significant amount of spectrally neutral darkening agents, such as magnetite.
However, Dawn’s Gamma Ray and Beutron Detector limits magnetite to only a few percent by mass. This means that an additional darkening agent—most likely amorphous carbon—must be present.
In addition, specific organic compounds were found near a 31-mile-wide impact crater named Ernutet, giving further support to the widespread presence of organic matter in Ceres’ shallow subsurface.
In the new study, the researchers found that 50-to-60 percent of Ceres’s upper crust could have a composition similar to primitive carbonaceous chondrite meteorites, which is compatible with contamination from infalling carbonaceous asteroids.
“Our results imply that either Ceres accreted ultra-carbon-rich materials or that carbon was concentrated in its crust,” Marchi said. “Both potential scenarios are important, because Ceres’s mineralogical composition indicates a global-scale event of rock-water alteration, which could provide conditions favorable to organic chemistry.”
The study was published in Nature Astronomy.