[Prev][Next][Index][Thread]

Re: (meteorobs) Meteor brightnesses and spectra



Lew Gramer wrote:

>This really piqued my questioning mind, Ed! What you're saying seems to
imply that there's a complex (i.e., nonlinear, discrete) relationship
between meteor velocities and meteor spectral peaks (or "colors", for lack
of a better word)!
>
You can ask the hardest questions!!  Not being an expert in the spectral
analysis of meteors, (few people are), I can give you some references to read.

See: Physics and Dynamics of Meteors - edited by Kresak & Millman 
     IAU Symposium 33 (1968) paper, "METEOR SPECTRA (Survey paper) by Ceplecha.
 
Quote: "The main meteor luminosity, (luminous head of the phenomonon)
consits almost entirely of atomic emission lines belonging to neutral and
ionized atoms of several elements, mainly atoms of the body itself."  "The
meteor spectrum changes with the velocity and the luminosity of the body.
The Ca+ lines H & K, are the main feature of fast meteors."  (This is at the
blue-violet end of the spectrum).  "their relative intensity to the lines of
neutral elements (Fe1) increases along the trajectory and is extremely high
in the meteor flares."
    " The Na1, Mg1 and Fe1 lines a dominent in the spectra of slow meteors."
"This fact is due to the velocity effect and not changes in the composition."

        (Na1- yellow and Mg1- green region of the spectrum)

You wrote:

 Also, are there shower-specific non-velocity factors which affect spectral
features? I'd assume there must be, with the variety of different origin
objects that spawn streams (Oort cloud comets, Kuiper belt comets, dead
comets and/or asteroids, maybe others too?)
>

                   Origins of Objects:

See paper:  METEOR SPECTRA - possible link between meteorite classes and
                             asteroid families. 
                By: Jiri Borovicka - Institute of Astronomy
                                     Ondrejov Observatory, Czech Republic

printed in: Seventy-Five Years of Hirayama Asteroid Families
                ASP Conference Series, Vol 63, 1994
        Yoshihide Kazai, Richard P. Binzel, and Tomohiro Hirayama (eds)

Jiri says: "It is shown that individual classes of achondrites can be
identified. Meteor spectroscopy, therefore provides an opportunity to study
the heliocentric orbits of achondrites and their relations to asteroid
families."

Hope this is of some help:  Ed

-----------------------------------------------------------------
Edward Majden                         epmajden@mars.ark.com
1491 Burgess Road                     Meteor Spectroscopy
Courtenay, B.C.                       CCD's - P.E.P.
CANADA  V9N-5R8                       Amateur Astronomy