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Non-random spatial distribution of impacts in
the Stardust cometary collector.
Westphal A. J., Bastien R. K., Borg J., Bridges J.,
Brownlee D. E., Burchell M. J., Cheng A. F., Clark B. C.,
Djouadi Z., Floss C., Franchi I., Gainsforth Z., Graham G.,
Green S. F., Heck P. R., Horányi M., Hoppe P.,
Hörz F. P., Huth J., Kearsley A., Leroux H., Marhas K.,
Nakamura-Messenger K., Sandford S. A., See T. H., Stadermann
F. J., Teslich N. E., Tsitrin S., Warren J. L.,
Wozniakiewicz P. J., and Zolensky M. E. (2007)
Lunar Planet. Sci. XXXVIII, Abstract #1418.
ABSTRACT
In January 2004, the Stardust spacecraft flew through the
coma of comet P81/Wild2 at a relative speed of 6.1 km/sec.
Cometary dust was collected at in a 0.1 m2
collector consisting of aerogel tiles and aluminum foils.
Two years later, the samples successfully returned to earth
and were recovered. We report the discovery that impacts in
the Stardust cometary collector are not distributed randomly
in the collecting media, but appear to be clustered on
scales smaller than 10 cm. We also report the discovery of
at least two populations of oblique tracks. We evaluated
several hypotheses that could explain the observations. No
hypothesis was consistent with all the observations, but the
preponderance of evidence points toward at least one impact
on the central Whipple shield of the spacecraft as the
origin of both clustering and lowangle oblique tracks.
High-angle oblique tracks unambiguously originate from a
non-cometary impact on the spacecraft bus just forward of
the collector. Here we summarize the observations, and
review the evidence for and against three scenarios that we
have considered for explaining the impact clustering found
on the Stardust aerogel and foil collectors.
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