(meteorobs) Color of photo meteor trails
epmajden at shaw.ca
Sun Nov 7 10:25:51 EST 2004
on 11/7/04 2:32, Roberto at me3540 at mclink.it wrote:
> Hi Ed,
> I do not have the scanner for to digitize the photographies.
> However I can analyze the colors as I have made for the leonids. As he said
> George must be attention to the colors. With the leonids I have tried to
> make corrections for color index taking as reference various spectral stars
> (the photos are not chased).
> Sorry for the English bad!
> Clear skies,
> Roberto Haver
Thank you again for your email. What I am primarily interested in is
the color of the high altitude portion of the meteor trail for meteors with
velocities of less than 40 km/sec. We have a Leonid photograph which we
have height data for and the trail starts out green. High velocity meteors
like the Leonids and Perseids often produce the O I forbidden green line at
557.7 nm which is present alone at high altitude, around 10 km higher than
the rest of the meteor spectrum. As the meteoroid penetrates lower into the
atmosphere other features develop and colors are then blends. The O I green
line is only present in meteors having velocities higher than 40 km/sec.
This is easy to see in meteor spectra. We are trying to see if the early
high altitude "green" sometimes recorded is associated with the O I
forbidden oxygen line at 557.7 nm. If this green is also present in slow
direct meteor tracks we cannot conclude that this is true unless actual
heights of the meteor are known.
Look at your direct color "slow" meteor photographs and let me know if
any of them show this "green" color at the high altitude end of the meteor
trail. I will report your comments to my colleague that is doing the
analysis of the triangulated Leonid trail. By the way, your English is just
fine, a lot better than my Italian!
Thank you again and clear skies.
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