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(meteorobs) Multi-colored meteors

   During the 98 Leonids, the brightest fireball of the night that I and my
observing partner witnessed seemed to have several colors
simultaneously...green, orange, and red most predominately, in a matrix of
silvery-white.  The colors seemed to sizzle into view as the meteor QUICKLY
reached its brightest magnitude.  I immediately questioned John about what
colors he saw, and he reported only two -  green and red - while I felt I saw a
very brief kaliedoscope of colors -- "patches" of different colors along the
length of the "tail" of the fireball, which was considerably foreshortened..not
far from being a true "pointer."

Kim S. Youmans

epmajden wrote:

>     I enjoyed reading Jim Bedients comments and useful references about
> meteor colors.  This is indeed a complex topic and controlled study of this
> might produce interesting information.  Meteor spectra have been obtained in
> a spectral region from around 350.0 nm, near UV to 900.0 nm, near IR.  With
> normal non extended red sensitive film, the region covered is from around
> 350.0 nm to 650.nm.  The eyes peak sensitivity centers on 550 nm or the
> green region of the spectrum.
>     It is difficult to say how much a dominant spectral line contributes to
> the visual color of the meteor.  The path of the meteor is a blend of all
> the lines present in the spectrum.  If the H & K lines of Ca+ at the blue
> end of the spectrum are the brightest lines recorded, the adding up of the
> other lines present will often be brighter than the Ca+ lines alone.  The
> resulting color is a combination of all of the lines.  I question even this!
> High velocity meteors such as the Perseids often record a strong neutral
> oxygen line at 557.7 nm.  This line is sometimes refered to as the forbidden
> auroral green line.  This line appears somewhat higher than the main
> spectrum and is often present by itself, or at least part of it is, and the
> color of the upper end of it is not confused by the blending of the other
> features measured in the spectrum.  It is also a persisent radiation lasting
> as long as 1 second.  If the color of the meteor is only dependent on the
> color of the spectral line, then such a meteor should start out yellow/green
> and then change to the color of all the blended features.  I have never seen
> this, have any of you?
>     I understand that an IMO group is experimenting with photographing the
> same meteor through different filters to see if the color index of the
> meteor can be determind.  It will be interesting to see the results they
> come up with.  I would also suggest using a high speed chopping shutter,
> just above the film, so the meteor is chopped up into nearly point sources.
> Each point could be measured to see if the color index changes along the
> path of the meteor.  Any comments about the color of meteors by
> professionals would be of interest to meteorobs readers.  Let's have some
> comments from them!
>
> Ed Majden
>
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