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Correlation between speed and size for ejecta from hypervelocity impacts
Author(s) -
Sachse M.,
Schmidt J.,
Kempf S.,
Spahn F.
Publication year - 2015
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
eISSN - 2169-9100
pISSN - 2169-9097
DOI - 10.1002/2015je004844
Subject(s) - ejecta , hypervelocity , micrometeoroid , interplanetary dust cloud , astrobiology , physics , interplanetary spaceflight , interplanetary medium , astrophysics , astronomy , space debris , solar system , solar wind , supernova , plasma , spacecraft , quantum mechanics
Ejecta created in hypervelocity impacts of micrometeoroids on atmosphereless bodies are an efficient source for circumplanetary and interplanetary dust. The impact erodes the target surface and releases material into space. The ejecta are typically micron sized and populate a dust cloud around the parent body, whose number density decreases with increasing distance from the target. Unbound particles escape and add to the planetary dust environment. Here we explore the influence of a correlation between the fragment size and the ejection speed, such that larger fragments are (on average) launched with lower speeds. This behavior is suggested by theoretical considerations and impact experiments. We find that such a correlation provides a dynamical filter that removes large ejecta from high altitudes. The effect is stronger for bigger ejecta and for more massive parent bodies. Our results suggest that large particles found in the circumplanetary and interplanetary dust environment either originate from impacts on smaller moons, impacts of unusually large or fast impactors, or an entirely different process of dust production.