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Record Details

Record 68 of 1723
Triton's cratering record and its time of capture
Author and Affiliation:
Strom, R. G.(Arizona Univ., Tucson, AZ, United States)
Croft, S. K.(Arizona Univ., Tucson, AZ, United States)
Abstract: Recent impact crater counts on the Voyager 2 high resolution images of Triton have resulted in a more accurate crater size/frequency distribution down to about 3 km diameter. These counts reveal a size/frequency distribution characterized by a differential -4 slope. This is consistent with the observation that there are no craters larger than 27 km diameter on the 20 percent of Triton viewed at resolutions capable of detecting them. A -4 slope is deficient in large craters and at the very low crater density on Triton no craters larger than about 30 km are expected on just 20 percent of the satellite. The Triton size distribution is significantly different from the differential -3 slope of the fresh crater population on Miranda, but both show leading/trailing asymmetries. Since Miranda is in prograde orbit this crater population is probably due to objects in heliocentric orbit, i.e., comets. If this crater population is due to comets, then the significantly different crater population on Triton is probably due to some other population of impacting objects. The most likely origin of these objects is planetesimals in planetocentric orbits. Because Triton is in retrograde orbit, objects in prograde planetocentric orbits will also produce a leading/trailing asymmetry. If the Triton craters are largely the result of objects in planetocentric orbit, then where are the comet craters that should be there if they have a differential -3 distribution function as inferred from the Miranda fresh crater population? The most likely answer is that they are there, but at such a low density that they can not be distinguished from the planetocentric population. An upper bound on this density can be estimated by determining the density of a crater population with a differential -3 slope where no craters larger than 27 km would be expected on the 20 percent of Triton viewed by Voyager at resolutions sufficient to detect them. This density is at the density of the largest crater. At this density the number of craters in size bins greater than 27 km is less than 1 for a -3 distribution function. The observed size distribution, the upper limit of the hypothetical comet crater size distribution, and the difference between the observed and the hypothetical comet crater populations is shown.
Publication Date: Jan 01, 1993
Document ID:
19940016329
(Acquired Dec 28, 1995)
Accession Number: 94N20802
Subject Category: LUNAR AND PLANETARY EXPLORATION
Coverage: Abstract Only
Document Type: Conference Paper
Publication Information: Lunar and Planetary Inst., Twenty-Fourth Lunar and Planetary Science Conference. Part 3: N-Z; p. p 1373-1374
Publisher Information: United States
Financial Sponsor: NASA; United States
Organization Source: Arizona Univ.; Lunar and Planetary Lab.; Tucson, AZ, United States
Description: 2p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: COMETS; DISTRIBUTION FUNCTIONS; METEORITE CRATERS; MIRANDA; PROJECTILE CRATERING; PROTOPLANETS; SIZE DISTRIBUTION; ESTIMATING; HIGH RESOLUTION; SOLAR ORBITS; VOYAGER 2 SPACECRAFT
Imprint And Other Notes: In Lunar and Planetary Inst., Twenty-Fourth Lunar and Planetary Science Conference. Part 3: N-Z p 1373-1374 (SEE N94-20636 05-91)
Availability Source: Other Sources
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