Bibcode
Bellot Rubio, L. R.; Ortiz, Jose L.; Sada, Pedro V.
Bibliographical reference
Earth, Moon, and Planets, v. 82/83, p. 575-598 (1998).
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1
2000
Citations
0
Refereed citations
0
Description
The first unambiguous detection of meteoroids impacting the night side
of the Moon was obtained during the 1999 Leonid storm. Up to eight
optical flashes were recorded with CCD video cameras attached to small
telescopes on November 18, 1999. Six impacts were videotaped by at least
two independent observers at the same times and lunar locations, which
is perhaps the strongest evidence for their collisional nature. The
flashes were clearly above the noise and lasted for less than 0.02 s.
Although previous observational efforts did not succeed in detecting
impact flashes, additional candidates have been reported in the
literature. The evidence accumulated so far implies that small
telescopes equipped with high speed cameras can be used as a new tool
for studying meteoroid streams, sporadic meteoroids, and hypervelocity
collisions. In this review we discuss the various intervening parameters
for detectability of flashes on the night side of the Moon (geometrical
effects, contamination by scattered light from the day side, and
properties of the meteoroids such as speed and flux of particles).
Particular emphasis is placed on the analysis of the observations in
order to derive relevant physical parameters such as luminous
efficiencies, impactor masses, and crater sizes. Some of these
parameters are of interest for constraining theoretical impact models.
From a simple analysis, it is possible to derive the mass distribution
of the impactors in the kg range. A more elaborate analysis of the data
permits an estimate of the fraction of kinetic energy converted to
radiation (luminous efficiency) if the meteoroid flux on the Moon is
known. Applied to the 1999 lunar Leonids, these methods yield a mass
index of 1.6 +/- 0.1 and luminous efficiencies of 2 × 10^-3 with
an uncertainty of about one order of magnitude. Predictions of
visibility of the major annual meteor showers are given for the next few
years. These include the forthcoming 2001 Leonid return, for which we
estimate detection rates in the visible.