Impact basins on Ganymede and Callisto and implications for the large-projectile size distribution

Details Impact basins on Ganymede and Callisto and implications for the large-projectile size distribution Impact basins on Ganymede and Callisto and implications for the large-projectile size distribution

Apr 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003eaeja....11475w&link_type=abstract

EGS - AGU - EUG Joint Assembly, Abstracts from the meeting held in Nice, France, 6 - 11 April 2003, abstract #11475

Mathematics

Logic

Scientific paper

It has been conjectured that the projectile family which impacted the Galilean Satellites of Jupiter was depleted in large projectiles, concluded from a ''dearth'' in large craters (> 60 km) (e.g. [1]). Geologic mapping, aided by spatial filtering of new Galileo as well as older Voyager data shows, however, that large projectiles have left an imprint of palimpsests and multi-ring structures on both Ganymede and Callisto (e. g. [2]). Most of these impact structures are heavily degraded and hence difficult to recognize. In this paper, we present (1) maps showing the outlines of these basins, and (2) derive updated crater size-frequency diagrams of the two satellites. The crater diameter from a palimpsest diameter was reconstructed using a formula derived by [3]. The calculation of the crater diameter Dc from the outer boundary Do of a multi-ring structure is much less constrained and on the order of Dc = k \cdot Do , with k ≈ 0.25-0.3 [4]. Despite the uncertainties in locating the ''true'' crater rims, the resulting shape of the distribution in the range from kilometer-sized craters to sizes of ≈ 500 km is lunar-like and strongly suggests a collisionally evolved projectile family, very likely of asteroidal origin. An alternative explanation for this shape could be that comets are collisionally evolved bodies in a similar way as are asteroids, which as of yet is still uncertain and in discussion. Also, the crater size distributions on Ganymede and Callisto are shifted towards smaller crater sizes compared to the Moon, caused by a much lower impact velocity of impactors which preferentially were in planetocentric orbits [5]. References: [1] Strom et al., JGR 86, 8659-8674, 1981. [2] J. E. Klemaszewski et al., Ann. Geophys. 16, suppl. III, 1998. [3] Iaquinta-Ridolfi &Schenk, LPSC XXVI (abstr.), 651-652, 1995. [4] Schenk &Moore, LPSC XXX, abstr. No. 1786 [CD-Rom], 1999. [5] Horedt & Neukum, JGR 89, 10,405-10,410, 1984.

Affiliated with

Also associated with

No associations

Rating

Impact basins on Ganymede and Callisto and implications for the large-projectile size distribution 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 Impact basins on Ganymede and Callisto and implications for the large-projectile size distribution, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Impact basins on Ganymede and Callisto and implications for the large-projectile size distribution will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-845022