The internal structure of JFC's. A Deep Impact contribution.
Abstract
We propose that the ubiquitous layering observed on the surface of 9P Tempel 1 during the Deep Impact mission 1 2 is an essential element of the internal structure of most Jupiter family comet nuclei We suggest that this layering is the natural outcome of low velocity collisions with other primitive Kuiper Belt bodies that must have occurred during the late accumulation stage of these objects in the solar nebula 6 In this picture the layers were laid down over 10 5 -- 10 6 yr 3 and some may have had very short exposure time to the nebula environment We envision a structural model for the interior called here the Talps or layered pile model that has an inner core transitioning to an outer mantle consisting of a sequence of thin randomly stacked layers each of limited area and possibly showing small differences in composition out to the surface As presented here this model predicts a correlation between the radial distance and the average thickness of the layers As long as gravity plays a minor role large nuclei are expected to have thicker surface layers and vice versa Mesas are formed following the suggestion by Britt et al 4 as a result of erosional sublimation at the boundaries of the outermost layers during passages near the sun Cometary splitting and tidal disruption is seen as the result of detachment of entire layers or possibly disassembly of essentially the entire presumably weakly bonded layer structure This model is related to the original primordial rubble pile model of Weissman 5 but is
- Publication:
-
36th COSPAR Scientific Assembly
- Pub Date:
- 2006
- Bibcode:
- 2006cosp...36.2124B