Scientists from ISMO, ICP and ISM used the CERISES instrument at the DESIRS beamline at SOLEIL to investigate how cyclopentadiene (C₅H₆)—a key building block of complex carbon and aromatic molecules—forms in cold interstellar clouds. By combining laboratory experiments and modeling, they identified new ion–molecule reactions and measured their rates, significantly improving predictions of its abundance.
Cold molecular clouds such as TMC-1 (Taurus Molecular Cloud-1) are key laboratories for understanding the build-up of molecular complexity in space. Over the past decade, radioastronomical surveys have revealed an unexpectedly rich inventory of cyclic and aromatic species, including cyclopentadiene (C₅H₆), indene (figure 1), and several cyano derivatives. However, despite these detections, astrochemical models have consistently underestimated the abundance of C₅H₆ by factors of several, highlighting a lack of reliable data about formation pathways from simple acyclic precursors toward the first five-membered aromatic ring.
Read more on the SOLEIL website