کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1781705 1022299 2010 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Models of high velocity impacts into dust-covered ice: Application to Martian northern lowlands
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فیزیک زمین (ژئو فیزیک)
پیش نمایش صفحه اول مقاله
Models of high velocity impacts into dust-covered ice: Application to Martian northern lowlands
چکیده انگلیسی

The detection of fresh impact craters with bright floors and ejecta (arising from fresh clean water ice) in the northern lowlands of Mars (Byrne et al., 2009b, Science 325, 1674), together with observations of polygonal structures and evidence from the Phoenix probe, suggests that there are substantial water ice deposits just below the surface over large areas. Specifically in cases of the larger craters observed, the impacts themselves may have raised the temperature and the pressure of the water ice deposits locally to values which allow phase changes. In this paper, we use smoothed particle hydrodynamics to model hyper-velocity impacts. We estimate peak shock pressures in a solid water ice target covered by a layer of loose material, modeled by pre-damaged dunite. In addition, we account for the possibility of a thin layer of sub-surface water ice by using a three-layer model where the ice is surrounded by dunite. We find that the peak shock pressures reached in the simulated events are high enough to produce several 100–1000 kg of liquid water depending upon the impact parameters and the exact shock pressure needed for the phase change. A difficulty remains however in determining whether liquid is generated or whether a type of fluidized ice is produced (or indeed some combination of the two). We also note that the process can become rather complex as the number of layers increases because of reflections of the shock at sub-surface boundaries—a process which should lead to increased fluidization.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Planetary and Space Science - Volume 58, Issue 10, August 2010, Pages 1160–1168
نویسندگان
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