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Article Dans Une Revue Nature Astronomy Année : 2023

UV-driven chemistry as a signpost of late-stage planet formation

Jenny K. Calahan
  • Fonction : Auteur
Edwin A. Bergin
  • Fonction : Auteur
Arthur D. Bosman
  • Fonction : Auteur
Evan A. Rich
  • Fonction : Auteur
Sean M. Andrews
  • Fonction : Auteur
Jennifer B. Bergner
  • Fonction : Auteur
L. Ilsedore Cleeves
  • Fonction : Auteur
Viviana V. Guzmán
  • Fonction : Auteur
Jane Huang
  • Fonction : Auteur
John D. Ilee
  • Fonction : Auteur
Charles J. Law
  • Fonction : Auteur
Karin I. Öberg
  • Fonction : Auteur
Richard Teague
  • Fonction : Auteur
Catherine Walsh
  • Fonction : Auteur
David J. Wilner
  • Fonction : Auteur
Ke Zhang
  • Fonction : Auteur

Résumé

The chemical reservoir within protoplanetary disks has a direct impact on planetary compositions and the potential for life. A long-lived carbon- and nitrogen-rich chemistry at cold temperatures (≤ 50 K) is observed within cold and evolved planet-forming disks. This is evidenced by bright emission from small organic radicals in 1-10 Myr aged systems that would otherwise have frozen out onto grains within 1 Myr. We explain how the chemistry of a planet-forming disk evolves from a cosmic-ray/X-ray-dominated regime to a ultraviolet-dominated chemical equilibrium. This, in turn, will bring about a temporal transition in the chemical reservoir from which planets will accrete. This photochemical dominated gas phase chemistry develops as dust evolves via growth, settling and drift, and the small grain population is depleted from the disk atmosphere. A higher gas-to-dust mass ratio allows for deeper penetration of ultraviolet photons is coupled with a carbon-rich gas (C/O > 1) to form carbon-bearing radicals and ions. This further results in gas phase formation of organic molecules, which then would be accreted by any actively forming planets present in the evolved disk.

Dates et versions

insu-04473235 , version 1 (22-02-2024)

Identifiants

Citer

Jenny K. Calahan, Edwin A. Bergin, Arthur D. Bosman, Evan A. Rich, Sean M. Andrews, et al.. UV-driven chemistry as a signpost of late-stage planet formation. Nature Astronomy, 2023, 7, pp.49-56. ⟨10.1038/s41550-022-01831-8⟩. ⟨insu-04473235⟩
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