Hi,
An excellent summary of the problems! As strategies evolve one of the things I continue to do (after the “discovery” of the rapid changes in spectrum of the bright Perseid, 2013) is to examine the spectrum videos frame by frame. This is in an effort to mitigate some of the very noise and absorption issues you mention. By taking the shortest possible “length” of spectrum to sum up to get a viable spectrum. The best, of course only need one frame but on others you need to use longer temporal sections.
I have been saying for years that meteor spectroscopy is a tricky proposition analytically speaking. There are a few published papers by Jeniskens that discuss “quantitative” spectroscopy but without some assumptions I’m not fully convinced (maybe I just don’t understand the maths!)
Nobody knows any physical information about the particular meteoroid that produces a particular spectrum beforehand and THAT is the problem. EVERY other aspect of the meteor we then capture is entirely random. Time, position, duration, luminous efficiency (and that’s the big one…) etc.
All we can determine with any certainty is the geocentric velocity, then comes along a spectrum carrying all these observational variables, did I mention tricky… ;-))
I think this is one of the reasons that the technique of comparing particular line ratio’s (as devised by Borovicka) is about as good as we can get.
HOWEVER even with qualitative results significant differences is spectrum characteristics can be identified and I think that’s why sporadics are the most interesting proposition and what I’ve called Comparative Meteor Spectroscopy can get us into some sort of new taxonomy over the coming years as data builds up.
Observers have been conducting meteor spectroscopy for a lot longer than me but these programs caught large fireballs on rare occasions but I think I’ve been the first to do regular video meteor spectroscopy, (in the UK?), and that’s only been since 2008 (or 2006 if you include my very first tests). So we’re only just starting a new field. Another 10 years and we’ll have a whole new picture of what’s in our planets neighbourhood.
All we can do is work with what we’ve got…
cheers,
Bill.