Quote:
Originally Posted by auroradude
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It just occurred to me - I wonder if the "split" tail look that is so prevelent in many images, especially the ones of the nucleus, is actually caused by the shadow of the inner (and denser) coma falling on the tail?
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Rob McNaught and I looked at this on my image of 18th Jan and some other images, it is definitely not a shadow, because it is curved! At the time the angle subtended by the sun from the comet was about 3 degrees, meaning that any shadow's cone would only be about 20 times as long as the diameter of the nucleus (plus dense nearby coma). The dark line clearly extends much further than this. I think we are just looking through an expanding cone of material and it appears darker where we see the least amount of dust (therefore least reflected sunlight).
cheers, Gordon