Discovery of organic compounds on Ceres
NASA’s Dawn mission revealed the presence of complex organic compounds on Ceres, the largest object in the asteroid belt between Mars and Jupiter. The origin of these molecules, whether due to external impacts or formed internally in the presence of brackish water, remains a topic of debate.
The Dawn mission discovered complex organic compounds on Ceres. While their origin remains a topic of debate, new research suggests that these molecules may have formed on Ceres itself. Future space missions aim to further explore these findings and the role of organic compounds in our solar system.
The discovery of aliphatic molecules on Ceres
One of the most interesting findings from NASA’s Dawn mission is that Ceres, the largest object in the asteroid belt between Mars and Jupiter, hosts complex organic compounds. The discovery of aliphatic molecules, which consist of chains of carbon and hydrogen, combined with evidence that Ceres has abundant water ice and may have been an ocean world, means that this dwarf planet may once have hosted key ingredients associated with life as we know it. .
Origins and impact on organic compounds.
How aliphatic organic compounds originated on Ceres has been the subject of intense research since their discovery in 2017. Some studies have concluded that a comet or other organic-rich impactor brought them to Ceres; Others indicate that the molecules formed on the dwarf planet after its primordial materials were altered by brackish water. But regardless of their origin, Ceres’ organic compounds have been influenced by the widespread impacts that have marked its surface.
Impacts and organic resilience
“Organic compounds were first detected in the vicinity of a large impact crater, which motivated us to examine how impacts affect these organic compounds,” says Terik Daly, a planetary scientist at the Johns Hopkins Applied Physics Laboratory who led this study. “We are finding that organic compounds may be more widespread than initially reported and that they appear to be resistant to the impacts of Ceres-like conditions.”
The importance of complete data
From the Dawn data, Daly knew that Ceres is covered in impact craters of various sizes formed when other asteroids collided with Ceres. But what he didn’t yet understand was how these impacts affect aliphatic compounds, the information needed to help determine where the organic compounds originated and how their signatures may have changed after being exposed to numerous impacts over billions of years. years.
Innovative data analysis
Rizos and Sunshine also performed a new analysis that combined data from two different instruments, the camera and imaging spectrometer flying on the Dawn spacecraft, and then used an algorithm to extrapolate composition information from the spectrometer to higher-resolution space. of the camera. The results allowed them to investigate organic compounds in greater detail than had been possible until now.
Information on organic origins and future explorations.
Taken together, the team’s analyzes point to some potentially interesting results.
“By leveraging the strengths of two different data sets collected on Ceres, we were able to map potentially organic-rich areas on Ceres with higher resolution,” says Rizos. “We can see a good correlation of organic compounds with older impact units and with other minerals such as carbonates that also indicate the presence of water. “While the origin of the organic compounds remains poorly understood, we now have good evidence that they formed on Ceres and probably in the presence of water.”
“There is the possibility that a large internal reserve of organic compounds is found within Ceres,” adds Rizos. “So, from my point of view, this result increases the astrobiological potential of Ceres.”
Expectations for a future mission to Ceres
For all team members, these results raised expectations for another mission to Ceres. In the latest decadal study on planetary science and astrobiology, “the US National Academy of Sciences approved the return of Ceres samples on the short list of high-priority mission targets,” says Rizos. “If that were to happen, it would be several decades from now. Meanwhile, new analyzes of existing data are a great way to make new discoveries.”
