Is cosmic dust porous?

Fuente: arXiv
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Main Authors: Potapov, Alexey, McCoustra, Martin R. S., Tazaki, Ryo, Bergin, Edwin A., Bromley, Stefan T., Garrod, Robin T., Rimola, Albert
Format: Preprint
Published: 2025
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author Potapov, Alexey
McCoustra, Martin R. S.
Tazaki, Ryo
Bergin, Edwin A.
Bromley, Stefan T.
Garrod, Robin T.
Rimola, Albert
author_facet Potapov, Alexey
McCoustra, Martin R. S.
Tazaki, Ryo
Bergin, Edwin A.
Bromley, Stefan T.
Garrod, Robin T.
Rimola, Albert
contents There is a long-standing discussion in the astrophysical/astrochemical community as to the structure and morphology of dust grains in various astrophysical environments (e.g., interstellar clouds, protostellar envelopes, protoplanetary and debris disks, and the atmospheres of exoplanets). Typical grain models assume a compact dust core which becomes covered in a thick ice mantle in cold dense environments. In contrast, less compact cores are likely to exhibit porosity, leading to a pronounced increase in surface area with concomitant much thinner ice films and higher accessibility to the bare grain surface. Several laboratory experimental and theoretical studies have shown that this type of dust structure can have a marked effect on several physico-chemical processes, including adsorption, desorption, mobility, and reactivity of chemical species. Porous grains are thus thought to likely play a particularly important and wide-ranging astrochemical role. Herein, we clarify what is meant by porosity in relation to grains and grain agglomerates, assess the likely astrochemical effects of porosity and ask whether a fractal/porous structural/morphological description of dust grains is appropriate from an astronomical perspective. We provide evidence for high porosity from laboratory experiments and computational simulations of grains and their growth in various astrophysical environments. Finally, we assess the observational constraints and perspectives on cosmic dust porosity. Overall, our paper discusses the effects of including porosity in dust models and the need to use such models for future astrophysical, astrochemical and astrobiological studies involving surface or solid-state processes.
format Preprint
id arxiv_https___arxiv_org_abs_2509_10292
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Is cosmic dust porous?
Potapov, Alexey
McCoustra, Martin R. S.
Tazaki, Ryo
Bergin, Edwin A.
Bromley, Stefan T.
Garrod, Robin T.
Rimola, Albert
Astrophysics of Galaxies
There is a long-standing discussion in the astrophysical/astrochemical community as to the structure and morphology of dust grains in various astrophysical environments (e.g., interstellar clouds, protostellar envelopes, protoplanetary and debris disks, and the atmospheres of exoplanets). Typical grain models assume a compact dust core which becomes covered in a thick ice mantle in cold dense environments. In contrast, less compact cores are likely to exhibit porosity, leading to a pronounced increase in surface area with concomitant much thinner ice films and higher accessibility to the bare grain surface. Several laboratory experimental and theoretical studies have shown that this type of dust structure can have a marked effect on several physico-chemical processes, including adsorption, desorption, mobility, and reactivity of chemical species. Porous grains are thus thought to likely play a particularly important and wide-ranging astrochemical role. Herein, we clarify what is meant by porosity in relation to grains and grain agglomerates, assess the likely astrochemical effects of porosity and ask whether a fractal/porous structural/morphological description of dust grains is appropriate from an astronomical perspective. We provide evidence for high porosity from laboratory experiments and computational simulations of grains and their growth in various astrophysical environments. Finally, we assess the observational constraints and perspectives on cosmic dust porosity. Overall, our paper discusses the effects of including porosity in dust models and the need to use such models for future astrophysical, astrochemical and astrobiological studies involving surface or solid-state processes.
title Is cosmic dust porous?
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2509.10292