Scientists from the Open University (OU) have analyzed isotopic measurements in the Martian atmosphere, providing new insights into the evolution of Martian climate throughout history and the origin of surface organics on Mars. Composed primarily of carbon dioxide (CO2), Mars’ atmosphere is rich in “heavy” carbon (13C) compared to Earth’s, due to the preferential release of “light” carbon (12C) into space over several billion years.

Scientists from the OU’s Atmospheric and Surface Research Group analyzed data from the ExoMars Trace Gas Orbiter (TGO) mission; These data show that carbon monoxide (CO) on Mars is consuming heavy carbon.

Dr. Juan Oldey, lead author of the published study Nature AstronomyHe explains: “The key to understanding why CO is less than 13°C lies in the chemical bond between CO.₂ and CO. When CO molecules₂ Destroyed by sunlight to form CO, 12 CO molecules₂ 13 more efficiently destroyed than CO₂this leads to 13 C depletion in CO2 over long periods of time.”

Despite the small amount of CO in the Martian atmosphere (less than 0.1%), these new measurements are important to our understanding of the evolution of Martian climate and may help determine the historical climatic conditions on Mars that made liquid water possible. early Martian surface. Dr Aldai commented, “We don’t know what the atmosphere was like on early Mars, and we don’t know what conditions allowed liquid water to flow on the surface. Carbon isotopes in the Martian atmosphere can help us estimate how much CO2 there is. _{it was} in the past

“New measurements by ExoMars TGO show that the planet is emitting less CO2 than previously thought, providing new constraints on the composition of this early Martian atmosphere.”

Recent measurements at the surface by NASA’s Curiosity rover showed a 13°C drop in the temperature of organic matter on the surface. Manish Patel, who leads the OU ExoMars research team, said: “There is a long-standing debate about whether organic matter on the surface of Mars is formed by biological or non-biological processes.

“The fact that both atmospheric carbon dioxide and surface organics have this 13 C-depleted isotopic signal that Huang measured may indicate that these organics are most likely of non-biological origin, but a different origin cannot be ruled out based solely on this information.”