Impacts into Titan's methane-clathrate crust as a source of atmospheric methane

Fuente: arXiv
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Autores principales: Wakita, Shigeru, Johnson, Brandon C., Soderblom, Jason M., Steckloff, Jordan K., Johnson, Alexandria V., Neish, Catherine D., Shah, Jahnavi, Corlies, Paul
Formato: Preprint
Publicado: 2025
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author Wakita, Shigeru
Johnson, Brandon C.
Soderblom, Jason M.
Steckloff, Jordan K.
Johnson, Alexandria V.
Neish, Catherine D.
Shah, Jahnavi
Corlies, Paul
author_facet Wakita, Shigeru
Johnson, Brandon C.
Soderblom, Jason M.
Steckloff, Jordan K.
Johnson, Alexandria V.
Neish, Catherine D.
Shah, Jahnavi
Corlies, Paul
contents Titan is the only icy satellite in the solar system with a dense atmosphere. This atmosphere is composed primarily of nitrogen with a few percent methane, which supports an active, methane-based hydrological cycle on Titan. The presence of methane, however, is intriguing, as its lifetime is likely much shorter than the age of the solar system due to its irreversible destruction by UV photolysis. To explain Titan's current atmospheric methane abundance, it is hypothesised that a replenishment mechanism is needed. One such mechanism may be crater forming impacts; a methane-clathrate layer potentially covering the surface of Titan may act as a reservoir that releases methane when disrupted by impacts. Here, we perform impact simulations into methane-clathrate layers to investigate the amount of methane released via impacts. Our simulations show that the amount of methane released into the atmosphere depends on both the impactor size and the methane-clathrate layer thickness. A single 20-km-diameter impactor releases up to 1% of Titan's current atmospheric methane mass; the effect of impact obliquity and surface porosity may further increase the released mass by a factor of 2-3. The release rate from impacts is lower than the net loss rate by photolysis, but the released methane mass via impacts can enhance the lifetime of methane in Titan's atmosphere by up to 3%. Menrva-sized (> 400 km diameter) crater-forming impacts directly liberate of $\sim$15% Titan's current atmospheric methane. The direct heating of the atmosphere by the impactor might contribute to additional crustal heating and methane release.
format Preprint
id arxiv_https___arxiv_org_abs_2503_19118
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Impacts into Titan's methane-clathrate crust as a source of atmospheric methane
Wakita, Shigeru
Johnson, Brandon C.
Soderblom, Jason M.
Steckloff, Jordan K.
Johnson, Alexandria V.
Neish, Catherine D.
Shah, Jahnavi
Corlies, Paul
Earth and Planetary Astrophysics
Titan is the only icy satellite in the solar system with a dense atmosphere. This atmosphere is composed primarily of nitrogen with a few percent methane, which supports an active, methane-based hydrological cycle on Titan. The presence of methane, however, is intriguing, as its lifetime is likely much shorter than the age of the solar system due to its irreversible destruction by UV photolysis. To explain Titan's current atmospheric methane abundance, it is hypothesised that a replenishment mechanism is needed. One such mechanism may be crater forming impacts; a methane-clathrate layer potentially covering the surface of Titan may act as a reservoir that releases methane when disrupted by impacts. Here, we perform impact simulations into methane-clathrate layers to investigate the amount of methane released via impacts. Our simulations show that the amount of methane released into the atmosphere depends on both the impactor size and the methane-clathrate layer thickness. A single 20-km-diameter impactor releases up to 1% of Titan's current atmospheric methane mass; the effect of impact obliquity and surface porosity may further increase the released mass by a factor of 2-3. The release rate from impacts is lower than the net loss rate by photolysis, but the released methane mass via impacts can enhance the lifetime of methane in Titan's atmosphere by up to 3%. Menrva-sized (> 400 km diameter) crater-forming impacts directly liberate of $\sim$15% Titan's current atmospheric methane. The direct heating of the atmosphere by the impactor might contribute to additional crustal heating and methane release.
title Impacts into Titan's methane-clathrate crust as a source of atmospheric methane
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2503.19118