Statistics
Scientific paper
Oct 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007dps....39.2309b&link_type=abstract
American Astronomical Society, DPS meeting #39, #23.09; Bulletin of the American Astronomical Society, Vol. 39, p.453
Statistics
Scientific paper
We find that secondary craters on Europa tend towards smaller depth-to-diameter (d/D) ratios than primary craters, consistent with observations on other cratered surfaces (the Moon and Mars). We measure craters near the resolution limit, so an individual crater profile is noisy and not definitive; however, the aggregate statistics of over 100 profiles demonstrate a systematic trend for shallow profiles.
Primary crater collapse from a simple bowl shape to a more shallow profile (or more complex morphology) is a function of material strength and surface gravity: the transition will happen at smaller diameters for weaker surfaces or for those with higher surface gravity. However, secondary craters are usually more shallow at a given diameter than a primary, perhaps due to lower fragment impact speeds or self-burial during
multiple, simultaneous impacts (McEwen and Bierhaus 2005).
To first order, very cold ice and rock respond similarly to impact cratering, with predictable differences due to differences in strength, equations of state, etc. But Europa's surface is enigmatic: pervasive fracturing suggests a solid, competent material; chaos features and mobility of blocks within chaos suggest fluid-like behavior; radar measurements (Black et al. 2001) support the presence of a porous surface layer, as do thermal inertia
models (Spencer 2004) -- though the thermal inertia only addresses the uppermost few cm. The d/D similarity of secondary craters on icy Europa and rocky surfaces (the Moon and Mars), whose surface evolutions are dominated by different processes, implies that either (a) material properties play a small role in the morphology of secondary craters, or (b) whatever processes operate to create Europa's surface features must leave the ice in a form that responds to cratering in a manner consistent with regoliths on other solar system surfaces.
NASA Outer Planets Program funds this research.
Bierhaus Edward B.
Chapman Clark R.
Schenk Paul M.
No associations
LandOfFree
Europa's Surface Properties from Secondary Crater Depth/Diameter Ratios does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Europa's Surface Properties from Secondary Crater Depth/Diameter Ratios, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Europa's Surface Properties from Secondary Crater Depth/Diameter Ratios will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1065387