Effective Reaction Temperatures of Irreversible Dust Chemical Reactions in a Protoplanetary Disk
Dust particles in protoplanetary disks experience various chemical reactions under different physicochemical conditions through their accretion and diffusion, which results in the radial chemical gradient of dust. We performed three-dimensional Monte Carlo simulations to evaluate the dust trajectori...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acf310 |
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| author | Lily Ishizaki Shogo Tachibana Tamami Okamoto Daiki Yamamoto Shigeru Ida |
| author_facet | Lily Ishizaki Shogo Tachibana Tamami Okamoto Daiki Yamamoto Shigeru Ida |
| author_sort | Lily Ishizaki |
| collection | DOAJ |
| description | Dust particles in protoplanetary disks experience various chemical reactions under different physicochemical conditions through their accretion and diffusion, which results in the radial chemical gradient of dust. We performed three-dimensional Monte Carlo simulations to evaluate the dust trajectories and the progress of fictitious irreversible reactions, of which kinetics is expressed by the Johnson–Mehl–Avrami equation. The distribution of the highest temperature that each particle experiences before the degree of reaction exceeds a certain level shows the lognormal distribution, and its mode temperature was used as the effective reaction temperature. Semi-analytical prediction formulas of the effective reaction temperature and its dispersion were derived by comparing a reaction timescale with a diffusive transport timescale of dust as a function of the reaction parameters and the disk parameters. The formulas reproduce the numerical results of the effective reaction temperatures and their dispersions within 5.5% and 24%, respectively, in a wide temperature range (200–1400 K). We applied the formulas for the crystallization of amorphous silicate dust and its oxygen isotope exchange with the H _2 O vapor based on the experimentally determined kinetics. For submicron-sized amorphous forsterite dust, the predicted effective reaction temperature for the oxygen isotope exchange was lower than that of crystallization without overlap even considering their dispersions. This suggests that the amorphous silicate dust in the protosolar disk could exchange their oxygen isotopes efficiently with the ^16 O-poor H _2 O vapor, resulting in the distinct oxygen isotope compositions from the Sun. |
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| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-11T15:38:24Z |
| publishDate | 2023-01-01 |
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| series | The Astrophysical Journal |
| spelling | doaj.art-b7febc6ae1c74c3688b477a9881b918f2023-10-26T13:15:22ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0195714710.3847/1538-4357/acf310Effective Reaction Temperatures of Irreversible Dust Chemical Reactions in a Protoplanetary DiskLily Ishizaki0https://orcid.org/0009-0005-8583-9730Shogo Tachibana1https://orcid.org/0000-0002-4603-9440Tamami Okamoto2https://orcid.org/0000-0003-1545-2723Daiki Yamamoto3https://orcid.org/0000-0001-6852-2954Shigeru Ida4https://orcid.org/0000-0001-9564-6186Department of Earth and Planetary Science, The University of Tokyo , Hongo, Tokyo 113-0033, Japan ; r.ishizaki@eps.s.u-tokyo.ac.jpDepartment of Earth and Planetary Science, The University of Tokyo , Hongo, Tokyo 113-0033, Japan ; r.ishizaki@eps.s.u-tokyo.ac.jpEarth-Life Science Institute, Tokyo Institute of Technology , Meguro, Tokyo 152-8550, JapanDepartment of Earth and Planetary Sciences, Kyushu University , Motooka, Nishi-ku, Fukuoka 819-0395, JapanEarth-Life Science Institute, Tokyo Institute of Technology , Meguro, Tokyo 152-8550, JapanDust particles in protoplanetary disks experience various chemical reactions under different physicochemical conditions through their accretion and diffusion, which results in the radial chemical gradient of dust. We performed three-dimensional Monte Carlo simulations to evaluate the dust trajectories and the progress of fictitious irreversible reactions, of which kinetics is expressed by the Johnson–Mehl–Avrami equation. The distribution of the highest temperature that each particle experiences before the degree of reaction exceeds a certain level shows the lognormal distribution, and its mode temperature was used as the effective reaction temperature. Semi-analytical prediction formulas of the effective reaction temperature and its dispersion were derived by comparing a reaction timescale with a diffusive transport timescale of dust as a function of the reaction parameters and the disk parameters. The formulas reproduce the numerical results of the effective reaction temperatures and their dispersions within 5.5% and 24%, respectively, in a wide temperature range (200–1400 K). We applied the formulas for the crystallization of amorphous silicate dust and its oxygen isotope exchange with the H _2 O vapor based on the experimentally determined kinetics. For submicron-sized amorphous forsterite dust, the predicted effective reaction temperature for the oxygen isotope exchange was lower than that of crystallization without overlap even considering their dispersions. This suggests that the amorphous silicate dust in the protosolar disk could exchange their oxygen isotopes efficiently with the ^16 O-poor H _2 O vapor, resulting in the distinct oxygen isotope compositions from the Sun.https://doi.org/10.3847/1538-4357/acf310Solar systemSolar system evolutionCosmochemistryAstrochemistryDust compositionProtoplanetary disks |
| spellingShingle | Lily Ishizaki Shogo Tachibana Tamami Okamoto Daiki Yamamoto Shigeru Ida Effective Reaction Temperatures of Irreversible Dust Chemical Reactions in a Protoplanetary Disk The Astrophysical Journal Solar system Solar system evolution Cosmochemistry Astrochemistry Dust composition Protoplanetary disks |
| title | Effective Reaction Temperatures of Irreversible Dust Chemical Reactions in a Protoplanetary Disk |
| title_full | Effective Reaction Temperatures of Irreversible Dust Chemical Reactions in a Protoplanetary Disk |
| title_fullStr | Effective Reaction Temperatures of Irreversible Dust Chemical Reactions in a Protoplanetary Disk |
| title_full_unstemmed | Effective Reaction Temperatures of Irreversible Dust Chemical Reactions in a Protoplanetary Disk |
| title_short | Effective Reaction Temperatures of Irreversible Dust Chemical Reactions in a Protoplanetary Disk |
| title_sort | effective reaction temperatures of irreversible dust chemical reactions in a protoplanetary disk |
| topic | Solar system Solar system evolution Cosmochemistry Astrochemistry Dust composition Protoplanetary disks |
| url | https://doi.org/10.3847/1538-4357/acf310 |
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