title: A study of interstellar aldehydes and enols as tracers of a cosmic ray-driven nonequilibrium synthesis of complex organic molecules.
abstract: Complex organic molecules such as sugars and amides are ubiquitous in star- and planet-forming regions, but their formation mechanisms have remained largely elusive until now. Here we show in a combined experimental, computational, and astrochemical modeling study that interstellar aldehydes and enols like acetaldehyde (CH3CHO) and vinyl alcohol (C2H3OH) act as key tracers of a cosmic-ray-driven nonequilibrium chemistry leading to complex organics even deep within low-temperature interstellar ices at 10 K. Our findings challenge conventional wisdom and define a hitherto poorly characterized reaction class forming complex organic molecules inside interstellar ices before their sublimation in star-forming regions such as SgrB2(N). These processes are of vital importance in initiating a chain of chemical reactions leading eventually to the molecular precursors of biorelevant molecules as planets form in their interstellar nurseries.
authors.affiliation: W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822; Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822;
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Abplanalp
authors.affiliation: Department of Chemistry, University of Southern California, Los Angeles, CA 90089;
authors.forename: Samer
authors.initials: S
authors.lastname: Gozem
authors.affiliation: Department of Chemistry, University of Southern California, Los Angeles, CA 90089;
authors.forename: Anna I
authors.initials: AI
authors.lastname: Krylov
authors.affiliation: Department of Chemistry, University of Virginia, Charlottesville, VA 22904;
authors.forename: Christopher N
authors.initials: CN
authors.lastname: Shingledecker
authors.affiliation: Department of Chemistry, University of Virginia, Charlottesville, VA 22904; Department of Astronomy, University of Virginia, Charlottesville, VA 22904.
authors.forename: Eric
authors.initials: E
authors.lastname: Herbst
authors.affiliation: W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822; Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822; ralfk@hawaii.edu.
authors.forename: Ralf I
authors.initials: RI
authors.lastname: Kaiser
keywords: astrochemistry; low-temperature kinetics; organics; photoionization; suprathermal chemistry