کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1773214 | 1021122 | 2013 | 13 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: The influence of imperfect accretion and radial mixing on ice:rock ratios in the Galilean satellites The influence of imperfect accretion and radial mixing on ice:rock ratios in the Galilean satellites](/preview/png/1773214.png)
• Impact-related mass loss cannot explain volatile-poor Io and Europa.
• Radial mixing efficiently smooths out initial compositional gradients.
• Tidal heating may help to explain volatile loss of inner moons.
We investigate the origin of the steep compositional gradient inferred for the Galilean satellites. We analyze N-body simulations of satellite accretion (Ogihara, M., Ida, S. [2012]. Astrophys. J. 753, 60) to: (1) determine the extent to which individual satellites accrete material from different semi-major axes (‘radial mixing’); and (2) calculate the change in rock:ice ratios due to vapor production or physical erosion during collisions. Because of inwards migration, satellites experience enough radial mixing that any initial compositional gradient is efficiently smoothed out. Mean-motion resonances generally prevent large proto-satellites from colliding with each other; as a result, neither vapor production nor physical erosion are capable of explaining the steep compositional gradient. According to the models presented here, even combining an initial compositional gradient with impact-related mass loss cannot reproduce the observed gradient. Some other physical process must have been responsible, perhaps tidally-driven volatile loss at Io and Europa. Impact-related mass loss was probably more important in the saturnian system, and may explain some of the observed satellite diversity there.
Journal: Icarus - Volume 225, Issue 1, July 2013, Pages 390–402