PRECIOUS · PREbiotic Chemistry to study the Interstellar Origin and evolUtion of Sugars

Sugars are crucial for the emergence of proteins, DNA, and ultimately living systems. Astronomers believe these molecules were originally produced from complex organic molecules (COMs) in space and later delivered to Earth by comets and asteroids. Yet, we still do not understand how sugars and COMs are formed there. Progress requires accurate chemical models, which can only be built if we know the molecular abundances and if we include all possible formation routes.For the robust determination of molecular abundances from spectra captured by telescopes, the competition between collisional and radiative processes must be accounted for. However, collisional data are missing for the vast majority of COMs (available for less than 10%). In addition, many formation paths in chemical models are also missing.A key COM precursor of sugars is glycolaldehyde, which has been observed in space many times. However, its origin and abundance remain highly uncertain. Its most abundant isomer, methyl formate, provides a valuable comparison to disentangle its possible formation routes.With the PRECIOUS project, I will develop an innovative strategy to fill this gap. I will design new methods to compute the missing collisional data, combining quantum and classical approaches supported by machine learning tools. Using these data, I will determine the abundances of glycolaldehyde and methyl formate in two molecular clouds rich in prebiotic chemistry, and I will employ newly developed chemical models to predict their abundances. This work will, for the first time, allow us to identify how glycolaldehyde is formed in space. By doing so, this project will provide crucial insights into the formation of the molecular building blocks of life.