2022 Fiscal Year Annual Research Report
Towards an absolute chronology of the outer Solar System
| Project/Area Number |
21J22854
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| Allocation Type | Single-year Grants |
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
WONG WAI EMILY 東京工業大学, 理学院, 特別研究員(DC1)
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| Project Period (FY) |
2021-04-28 – 2024-03-31
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| Keywords | Outer solar system / Icy satellites / Crater chronology / Giant planet migration |
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| Outline of Annual Research Achievements |
This study aims to determine the age of the giant planets' regular satellites and the cratering/impacting rate of the outer solar system. Our recent efforts have focused on the icy regular satellites of Saturn. To achieve this, we used high-resolution outer solar system evolution simulations and improved estimates of the number of trans-Neptunian objects from the literature. This enabled us to calculate model surface ages of the most heavily cratered terrains on icy satellites, which have implications for understanding the formation and tidal evolution of these satellites.
We found that the surface ages of the cratered plains on Mimas, Enceladus, Tethys, Dione, and Rhea range from 4.1 Ga to 4.4 Ga, with the surfaces of Mimas and Enceladus being roughly 200 million years younger than the outer three satellites. The calculated model surface ages are consistent with the idea that Saturn's regular satellites are ancient and have implications for their formation and tidal evolution. This work provides updated isochrons (please refer to the figures) for the observed crater size-frequency measurement of the icy satellites and supports the current understanding of the satellites' formation and evolution.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Underestimated the computational time required to complete the N-body simulation of the Outer Solar System for 4.5 Gyrs of evolution.
Unable to initiate in-depth discussion with overseas collaborators due to international travel restriction in the past two years.
We will be submitting our first manuscript of this project by the end of April 2023.
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| Strategy for Future Research Activity |
We have been running more simulations to constrain the evolving cratering rate and possibility the impact probability in more recent time. We seek to validate our obtained surface ages by extrapolating from the current cratering rate in the manner of Zahnle et al. 2003, and thereby to provide more accurate ages for young surfaces.
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Research Products
(3 results)
