(meteorobs) (Meteorobs) comment on being green

[Chris Peterson]

I don't believe there is much evidence to support the idea that meteor 
color (as seen with the eye) has much relationship to the meteoroid 
composition- at least, when we are talking about fireballs. There is 
good evidence, however, that the color is mainly the from ionization of 
atmospheric gas- especially oxygen. I've personally collected images of 
several bright fireballs through a 501 nm narrow band (6 nm) filter, 
which argues for a very strong [OIII] component to the light.

FWIW, a quick review of the meteor reports (nearly all fireballs) I've 
received in the last 11 years shows this:

9110 reports total
3735 (41%) report some sort of color
3069 (82% of those reporting color) report some shade of green

I've long since concluded that bright fireballs are almost always green. 
The exceptional cases are those which are not (and these are almost 
always reported as white).

The only other color that tends to show up in witness descriptions is 
red/orange, and a close look reveals that this is almost always at the 
end of the path, when it is easily explained as the output of a cooling 
blackbody radiator.

Chris

*******************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

On 10/17/2011 9:33 AM, drobnock wrote:
> It has been suggested that the green meteor trails are from the
> ionization of oxygen or the excitation of the oxygen atoms. So is it
> proper to state -- for those interested in green trails - that  green
> meteor trails are green  at 100 km up to about 150 km. Red oxygen meteor
> trails  are 150 km upwards to 250 km and more rarely to 600 km plus?
>
> Is the composition of the meteor and the colour of the trail
> attribured to the mineral composition? Per flame test of minerals. For
> example  a red meteor may be  -  Red because Both lithium and strontium
> produce a red flame and the strontium flame is brighter red.  or
> Orange/yellow Calcium burns with an orange flame. Sodium burns bright
> yellow. or Green A number of elements generate flames in the green
> spectrum. Barium and molybdenum produce yellowish-green flames. Boron
> creates a bright green colour. Thallium burns pure green. Phosphorus and
> zinc burn bluish green. or Blue Selenium, indium and arsenic burn blue.
> http://www.ehow.com/info
>
> George John Drobnock
>