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Main Authors: Miyayama, Ryushi, Schaefer, Laura Kay, Kobayashi, Hiroshi, Zorzi, Andrea
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2507.10369
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author Miyayama, Ryushi
Schaefer, Laura Kay
Kobayashi, Hiroshi
Zorzi, Andrea
author_facet Miyayama, Ryushi
Schaefer, Laura Kay
Kobayashi, Hiroshi
Zorzi, Andrea
contents Meteoroid entry into planetary atmospheres generates bow shocks, resulting in high-temperature gas conditions that drive chemical reactions. In this paper, we perform three-dimensional hydrodynamic simulations of meteoroid entry using the Athena++ code, coupled with chemistry calculations via Cantera to model the non-equilibrium chemistry triggered by atmospheric entry. Our aerodynamical simulations reveal the formation of complex shock structures, including secondary shock waves, which influence the thermodynamic evolution of the gas medium. By tracking thermodynamic parameters along streamlines, we analyze the effects of shock heating and subsequent expansion cooling on chemical reaction pathways. Our results demonstrate that chemical quenching occurs when the cooling timescale surpasses reaction rates, leading to the formation of distinct chemical products that deviate from equilibrium predictions. We show that the efficiency of molecular synthesis depends on the object\textquotesingle s size and velocity, influencing the composition of the post-entry gas mixture. Applying our model to Titan, we demonstrate that organic matter can be synthesized in the present environment of Titan. Also, we find that nitrogen, the dominant atmospheric component, remains stable, while water vapor is efficiently removed, a result inconsistent with equilibrium chemistry assumptions. Moreover, we compare our simulation results with laser experiments and find good agreement in chemical yields. Finally, we also evaluate the impact on Titan\textquotesingle s atmosphere as a whole, showing that meteoroid entry events could have played a significant role in supplying molecules such as HCN during early Titan\textquotesingle s history.
format Preprint
id arxiv_https___arxiv_org_abs_2507_10369
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Modeling Atmospheric Alteration on Titan: Hydrodynamics and Shock-Induced Chemistry of Meteoroid Entry
Miyayama, Ryushi
Schaefer, Laura Kay
Kobayashi, Hiroshi
Zorzi, Andrea
Earth and Planetary Astrophysics
Meteoroid entry into planetary atmospheres generates bow shocks, resulting in high-temperature gas conditions that drive chemical reactions. In this paper, we perform three-dimensional hydrodynamic simulations of meteoroid entry using the Athena++ code, coupled with chemistry calculations via Cantera to model the non-equilibrium chemistry triggered by atmospheric entry. Our aerodynamical simulations reveal the formation of complex shock structures, including secondary shock waves, which influence the thermodynamic evolution of the gas medium. By tracking thermodynamic parameters along streamlines, we analyze the effects of shock heating and subsequent expansion cooling on chemical reaction pathways. Our results demonstrate that chemical quenching occurs when the cooling timescale surpasses reaction rates, leading to the formation of distinct chemical products that deviate from equilibrium predictions. We show that the efficiency of molecular synthesis depends on the object\textquotesingle s size and velocity, influencing the composition of the post-entry gas mixture. Applying our model to Titan, we demonstrate that organic matter can be synthesized in the present environment of Titan. Also, we find that nitrogen, the dominant atmospheric component, remains stable, while water vapor is efficiently removed, a result inconsistent with equilibrium chemistry assumptions. Moreover, we compare our simulation results with laser experiments and find good agreement in chemical yields. Finally, we also evaluate the impact on Titan\textquotesingle s atmosphere as a whole, showing that meteoroid entry events could have played a significant role in supplying molecules such as HCN during early Titan\textquotesingle s history.
title Modeling Atmospheric Alteration on Titan: Hydrodynamics and Shock-Induced Chemistry of Meteoroid Entry
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2507.10369