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djswan2002's picture
Last seen: 1 day 3 hours ago
Joined: 20/04/2017 - 19:58
Na tail

Very nice, Robin. Is there very much in the literature on the spatial distribution of the various components in comets longitudinally through an apparition? If only bright-ish comets coming close-ish to Earth were more frequent...

Robin Leadbeater's picture
Last seen: 11 hours 21 min ago
Joined: 05/03/2014 - 00:50

Thanks David,

I approached this not knowing much about it just to see what might be possible to measure but think there is other pro work like this around, though most of it seems to be concentrated on the coma rather than the tail. I've not seen anything like this by amateurs though. In fact I cannot recall seeing amateur tail spectra of any comet and it was quite a surprise when I recorded it as it looked so different to the coma spectra you usually see, with CO+  in place of C2.  The Sodium distribution looks similar to what the PSI team got  which is what I was mainly interested in trying to pick up.

How far the CN spreads surprised me. I suspect the distribution across the tail actually spreads much further even than my plot suggests. The measured distribution approaches zero steeply rather than gradually tailing off suggesting it is clipped. It likely extended beyond the ends of the slit so was clipped when I used the edges of the field to subtract the sky background. 

It would be nice to measure further out along the tail but I already had to stitch 2 slit lengths together to cover the width of the tail even this close in.