The rapid formation of macromolecules in irradiated ice of protoplanetary disk dust traps

Abstract

Organic macromolecular matter is the dominant carrier of volatile elements such as carbon, nitrogen, and noble gases in chondrites -- the rocky building blocks from which Earth formed. How this macromolecular substance formed in space is unclear. We show that its formation could be associated with the presence of dust traps, which are prominent mechanisms for forming planetesimals in planet-forming disks. We demonstrate the existence of heavily irradiated zones in dust traps, where small frozen molecules that coat large quantities of microscopic dust grains could be rapidly converted into macromolecular matter by receiving radiation doses of up to several 10s of eV molecule${}^{-1}$ year${}^{-1}$. This allows for the transformation of simple molecules into complex macromolecular matter within several decades. Up to roughly 4$\%$ of the total disk ice reservoir can be processed this way and subsequently incorporated into the protoplanetary disk midplane where planetesimals form. This finding shows that planetesimal formation and the production of organic macromolecular matter, which provides the essential elemental building blocks for life, might be linked.

16 pages, 5 figures, Accepted in Nature Astronomy 10 July 2024, Published 30 July 2024

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Cited by in corpus (5)

• Chemical transformation of CO in evolving protoplanetary discs across stellar masses: a route to C-rich inner regions
• Models and Observational Predictions of Dust Traps in Protoplanetary Discs
• Stopping cross-section for protons across different phases of water
• Spatial distribution of organics in the Horsehead nebula: Signposts of chemistry driven by atomic carbon
• Observational evidence for a possible link between PAH emission and dust trap locations in protoplanetary disks