Astrochemistry

Journey of Complex Organic Molecules: Formation and Transport in Protoplanetary Disks

By Keith Cowing

Status Report

astro-ph.EP

December 13, 2024

Filed under astro-ph.EP, astrochemistry, astrogeology, exoplanet, planet formation, Protoplanetary Disk

Journey of Complex Organic Molecules: Formation and Transport in Protoplanetary Disks — Two-dimensional temperature map of the disk after 300 kyr of evolution, showing the methanol iceline at t = 0 (dashed blue line) and at t = 300 kyr (solid blue line). The white curve represents the average trajectory of 500 simulated particles. To provide a clearer illustration of individual particle behavior, the insets on the right display the trajectory of a single particle within the disk. The panels illustrate the trajectories of particles with sizes of 1 cm, 100 µm, and 1 µm, released at disk temperatures of 20 K (panels a, b, and c) and 80 K (panels d, e, and f). Initial and final positions are marked by a green triangle and a green cross, respectively. — astro-ph.EP

Complex organic molecules serve as indicators of molecular diversity. Their detection on comets, planets, and moons has prompted inquiries into their origins, particularly the conditions conducive to their formation.

One hypothesis suggests that the UV irradiation of icy grains in the protosolar nebula generates significant molecular complexity, a hypothesis supported by experiments on methanol ice irradiation. We investigated the irradiation of methanol ice particles as they migrate through the protosolar nebula.

Our objective is to ascertain whether the encountered conditions facilitate the formation of complex organics molecules, and we leverage experimental data in our analysis. We developed a two-dimensional model that describes the transport of pebbles during the evolution of the protosolar nebula, employing a Lagrangian scheme.

This model computes the interstellar UV flux received by the particles along their paths, which we compared with experimental values. On average, particles ranging from 1 to 100 micrometers in size, released at a local temperature of 20 K, undergo adequate irradiation to attain the same molecular diversity as methanol ice during the experiments within timescales of 25 kyr of protosolar nebula evolution.

In contrast, 1 cm sized particles require 911 kyr of irradiation to reach similar molecular diversity, making comparable molecular complexity unlikely. Similarly, particles ranging from 1 to 100 micrometers in size, released at a local temperature of 80 K, receive sufficient irradiation after 141 and 359 kyr. The particles readily receive the irradiation dose necessary to generate the molecular diversity observed in the experiments within the outer regions of the disk.

Our model, combined with future irradiation experiments, can provide additional insights into the specific regions where the building blocks of planets form.

T. Benest Couzinou, O. Mousis, G. Danger, A. Schneeberger, A. Aguichine, A. Bouquet

Comments: 12 pages, 7 figures. Published in A&A
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2412.09271 [astro-ph.EP] (or arXiv:2412.09271v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2412.09271
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Journal reference: Astronomy & Astrophysics, December 2024, Volume 692, id.A10, 11 pp
Related DOI:
https://doi.org/10.1051/0004-6361/202449499
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Submission history
From: Tom Benest Couzinou
[v1] Thu, 12 Dec 2024 13:32:37 UTC (4,143 KB)
https://arxiv.org/abs/2412.09271
Astrobiology,

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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