Astronomers provide new insight into the evolution of the Martian atmosphere

Scientists at the Open University (OU) have analyzed isotopic measurements in the Martian atmosphere, providing new information on the evolution of the Martian climate throughout history and the origin of organic matter on Mars.

the atmospheres Mars, which mostly consists of Carbon Dioxide (Co₂), which is relatively enriched in “heavy” carbon (¹³c) with respect to Earth due to preferential escape of “light” carbon (¹²c) into space over several billion years.

Scientists from OU’s Atmospheric and Surface Exploration Group analyzed data from the ExoMars Trace Gas Orbiter (TGO) mission, which indicates that Martian carbon monoxide (CO) has been depleted in heavy carbon instead.

Dr. Juan Alday, lead author of the study published in natural astronomyHe explains, “The key to understanding why there is less ¹³C in CO lies in the chemical relationship between CO₂ and CO. When CO₂ The molecules are destroyed by sunlight to form carbon dioxide, ¹²co₂ particles are destroyed more efficiently than ¹³co₂which leads to exhaustion ¹³C in CO over long periods of time. ”

Despite the small amount of carbon dioxide in the Martian atmosphere (less than 0.1%), these new measurements have important implications for our understanding of the evolution of the Martian climate and could help determine the historical climatic conditions that enabled the presence of liquid water on Mars. surface of early Mars.

Dr Al-Day commented: “We don’t know what the early Mars atmosphere was like nor the conditions that allowed liquid water to flow at the surface. Carbon isotopes in the Martian atmosphere can help us estimate the amount of carbon dioxide.₂ There was in the past.

New measurements by the ExoMars TGO indicate a decrease in carbon dioxide₂ It spared more of the planet than previously thought and imposed new constraints on the composition of this early Mars atmosphere.”

Recent measurements by NASA’s Curiosity Rover of the surface revealed depletion ¹³C in the surface Organic materials.

Manish Patel, who leads the OU ExoMars research group, said, “There is a long-standing debate about whether organic materials on Mars resulted from biological or non-biological processes.

The fact that both atmospheric carbon dioxide and Surface Organics shares this ¹³The C-depleted isotope signature measured by Guan may indicate that these organics are likely to be non-biological in origin, although other origins cannot be ruled out based solely on this information.”