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Pluto's ocean is capped and insulated by gas hydrates
| Title: | Pluto's ocean is capped and insulated by gas hydrates |
| Authors: | Kamata, Shunichi Browse this author →KAKEN DB | | Nimmo, Francis Browse this author | | Sekine, Yasuhito Browse this author | | Kuramoto, Kiyoshi Browse this author | | Noguchi, Naoki Browse this author | | Kimura, Jun Browse this author | | Tani, Atsushi Browse this author |
| Issue Date: | Jun-2019 |
| Publisher: | Nature Publishing Group |
| Journal Title: | Nature Geoscience |
| Volume: | 12 |
| Issue: | 6 |
| Start Page: | 407 |
| End Page: | 410 |
| Publisher DOI: | 10.1038/s41561-019-0369-8 |
| Abstract: | Many icy Solar System bodies possess subsurface oceans. On Pluto, Sputnik Planitia's location near the equator suggests the presence of a subsurface ocean and a locally thinned ice shell. To maintain an ocean, Pluto needs to retain heat inside. On the other hand, to maintain large variations in its thickness, Pluto's ice shell needs to be cold. Here we show, by thermal evolution and viscous relaxation calculations, that the presence of a thin layer of clathrate hydrates (gas hydrates) at the base of the ice shell can explain both the long-term survival of the ocean and the maintenance of shell thickness contrasts. Clathrate hydrates act as a thermal insulator, preventing the ocean from completely freezing while keeping the ice shell cold and immobile. The most likely clathrate guest gas is methane, derived from precursor bodies and/or cracking of organic materials in the hot rocky core. Nitrogen molecules initially contained and/or produced later in the core would probably not be trapped as clathrate hydrates, instead supplying the nitrogen-rich surface and atmosphere. The formation of a thin clathrate hydrate layer cap to a subsurface ocean may be an important generic mechanism to maintain long-lived subsurface oceans in relatively large but minimally heated icy satellites and Kuiper belt objects. |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/76168 |
| Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 鎌田 俊一
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