Photochemical Production of Short-Chain Carboxylic Acids From Carbonaceous Chondritic Precursors Under Mars-Like Conditions

Introduction: In the search for life on Mars, deconvolving the origin of organic carbon (OC) crucial. A complex, mixed signal from multiple sources is expected, including exogenous in fall, in situ abiotic synthesis, and potentially life. Post-depositional processing, especially through radiation, can alter OC. Meteoritic organics are well-understood, but their evolution in the Martian environment has not been constrained, where a thinner atmosphere allows a higher flux of solar photons to reach the surface, especially organics-damaging short-wavelength UVC (~190 nm+). UV can degrade, transform, and/or synthesize organics; effects vary by molecule/functional group and associations with photoprotective or catalytic minerals. Constraining these processes is key to elucidating sources and sinks of carbon on Mars and predicting the abiotic background that must be deconvolved for life detection in situ and with future returned samples.