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(meteorobs) Looking for help with research about meteor width
Hi everyone,
I am writing this letter to ask for the help of your observatory
with a research project which is in progress at Mount Allison
University. We are trying to determine the width of the luminous
column in meteor ablation trails. Obtaining telescopic CCD images
which contain chance passages of meteors are needed for one portion
of our research.
Conventional ablation theory suggests that the width should only be
a few meters wide, but with meteoroid fragmentation the width may be
significantly greater than this. As recently overviewed by our
research group (Fisher et al., 2000, Planet. Space Sci., 48, 911)
most cometary meteors are "dustballs" which contain large numbers or
fundamental grains. On a small selection of Leonid meteors we have
identified significant transverse spread in the luminous column
(Murray et al., 1999, Meteoritics Planet. Sci., 34, 949) and we have
detected jet-like features in at least a few meteors (LeBlanc et al.,
2000, Mon. Not. R. astr. Soc., 313, L9). Subsequently the diffuse
nature of some Leonid meteors have been confirmed by others (Spurny
et al., 2000, Meteoritics Planet. Sci., 35, 1109; Taylor et al.,
2000, Earth Moon Planets, 82/83, 379). Therefore the width of meteor
trails is of much current interest. The question is of importance
for several reasons: it may help constrain the size distribution of
the fundamental dust grains from which cometary meteoroids formed in
the primordial solar system; an understanding of the width of the
ionization column is necessary for calibration of meteor radar
systems; and the interaction of meteoroids with spacecraft and the
associated risks depend to some degree on the structure and
fragmentation state of the meteoroid.
Hawkins and Whipple (Astron. J., 1958, 63, 283) found, using
photographic plates from telescopic images, that meteor images were
significantly wider than star images of comparable intensity. They
hypothesized that this width was a result of fragmentation.
Essentially we are hoping to repeat their analysis using CCD based
telescopic meteor images.
We have collected a variety of images using our own wide-field
microchannel plate image intensified CCD cameras, but these only
have sufficient spatial resolution to detect extensive width in the
ablation column. To supplement our data, we require high resolution
telescopic images; even a few images would be of great value to our
research.
We are mainly interested in images taken with telescopes of focal
length more than 500 mm.
We will, of course, give credit to the observer and observatory in
any publication of our research results.
Yours sincerely,
Chris Pollock
Mount Allison University
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