An illustration reveals how neutron transfer in the soil can affect isotopic rations in the atmosphere. Photo by NASA/GSFC/JPL-Caltech
GREENBELT, Md., Sept. 30 (UPI) -- New isotopic analysis by the Curiosity rover's Sample Analysis at Mars, or SAM, instrument suite suggests the Red Planet's surface has contributed to the evolution of the Martian atmosphere.
After Curiosity measured and analyzed isotopic ratios of xenon and krypton in the Martian atmosphere, NASA scientists compared the results to measurements made during the Viking mission.
The story of Mars' atmosphere has been a mostly uncomplicated narrative of loss. The planet once held a significant atmosphere, but over time, solar wind has stripped Mars of its gas.
The latest analysis -- detailed in the journal Earth and Planetary Science Letters -- offers a slightly more complicated story. The new data mostly matches with the Viking mission analysis, but scientists uncovered some slight changes in isotopic ratios.
An isotope is an element with a unique number of neutrons. Researchers believe neutron transfers between elements in Martian soil may explain the isotopic changes in the atmosphere.
Specifically, barium may have had neutrons appropriated by xenon, while bromine may have surrendered neutrons to krypton. As a result, the Martian soil may have accumulated higher levels of the isotopes xenon-124 and 126, as well as krypton-80 and krypton-82.
Over time, meteor impacts could have released these unique isotopes from loose soil and rocks into the atmosphere.
"SAM's measurements provide evidence of a really interesting process in which the rock and unconsolidated material at the planet's surface have contributed to the xenon and krypton isotopic composition of the atmosphere in a dynamic way," Pamela Conrad, SAM's deputy principal investigator at the Goddard Space Flight Center, said in a news release.
"The unique capability to measure in situ the six and nine different isotopes of krypton and xenon allows scientists to delve into the complex interactions between the Martian atmosphere and crust," added Michael Meyer, lead scientist for the Mars Exploration Program at NASA's headquarters. "Discovering these interactions through time allows us to gain a greater understanding of planetary evolution."