Meteor spectroscopy of fireball

[Martin Dubs]

Hello,

I would like to present some recent results on a topic not regularly covered here. Yesterday a bright (-8mag) fireball was observed in Switzerland by several stations of the Swiss Meteor Network (Fachgruppe Meteorastronomie). From the same meteor visual, photographic, video, radio and spectroscopic mesurements were obtained simultaneously. From these observations the flight path could be reconstructed. If it had not exploded high up in the atmosphere, it would have landed close to one of the observers for easy collection. Details you can find here:
http://www.meteorastronomie.ch/ergebnisse.html
The results on the spectroscopy of this meteor and video spectrum you find further down on the page. I analyzed the beginning of the meteor spectrum by registering and stacking 8 video fields (160ms total exposure)

stacked spectrum of beginning

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and the stationary afterglow by adding 7 video fields.

raw spectrum of trail

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The brightest part of the meteor recording was completely overexposed, not suitable for analysis.
I may add that the spectra were linearized before stacking with a new method described here (basically a transformation of the video images to an orthographic projection):
http://www.meteorastronomie.ch/images/M ... _part2.pdf
This is important for spectra recorded with a wide angle camera, dispersion is dependent on meteor position.
Further processing (stacking, correction of slant, addition of rows etc. as well as extracting the images from the video, background subtraction etc.) was done in IRIS, plotting in ISIS.
The analyzed spectra (not corrected for instrument response) show large differences, with the O I line at 7774A missing in the afterglow and the intensities of the Mg I (5178) and Na I (5890) reversed in the two spectra.

comparison beginning and trail

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The forest of lines around 4000A has not been fully identified (Fe, Mg, Ca):

zoom on spectrum of beginning

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Regards, Martin

[Paolo Berardi]

Hi Martin, interesting to see an excellent method to compensate the field distortion for the spectral profile extraction. I didn't know the Swiss Meteor Network. They are doing a great job!

Thanks for sharing!

Paolo

[Robin Leadbeater]

Certainly a big improvement over my feeble efforts a few years ago . We need still larger format camera sensors to match the resolution and capture area of film cameras though. I still dream of running a large format CCD camera with a nice wide field APO lens and an objective grating continuously with short exposures every clear night. I just need someone to buy it for me

Robin

[Martin Dubs]

Hello,

in the meantime some more spectra have beeen recorded of Perseids. The results are presented here:
http://www.meteorastronomie.ch/ergebnis ... ktroskopie
Here an example:

2 Perseid spectra during the night of Aug. 12/13

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In addition, my method used for calibrating meteor spectra has been published together with Peter Schlatter in a paper in the Journal of the International Meteor Organisation. It can be downloaded here:
http://www.meteorastronomie.ch/images/M ... 4_2015.pdf
In the same issue of the journal there are other papers on meteor spectroscopy by Bill Ward. It seems that meteor spectroscopy is becoming increasingly popular. In part this may be because recording video spectra is fully automatic, the analysis can be done anytime, e.g. during a rainy weekend.

Best regards,

Martin