| 研究実績の概要 |
Conflicting ideas about Enceladus’ interior come from predictions of its tidal history, an uncertain bombardment history, and a limited understanding of the crater. So, we combine the latest computer models of outer Solar System and a new massive database of Enceladus’ craters to study the geological history of its icy surface. We calculated that Enceladus' oldest parts, around the North Pole, have been frozen for over 4.1 billion years. Its trailing and leading hemispheres have resurfaced at least three times in the past 3 billion years; those regions look fresher and smoother. The most recent resurfacing event was about 10 million years ago. This timing lines up with when Enceladus might have heated up from the tides and helps us constrain the tidal history of the Saturnian moon system.
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