[BAA Comets] C/2015V2 tail puzzle

[Gianantony]

Hi Peter and all,

there is some apparent confusion about the anti tail on this comet. It 
is true that dust antitails are often quite narrow and opposite to a 
larger main dust tail, but this is not the case.  The narrow tail is the 
ion tail, and it is close to the prolonged radius vector. The antitail 
is the larger dust tail.  Due to the particular line of sight the two 
tails (ion and dust) are seen in different directions causing the 
curious shape of the comet.
So here the antitail is the main dust tail.

Best regards

Giannantonio Milani

Il 29/05/2017 15:17, Peter Carson ha scritto:
> Hi All,
> I’m puzzled by the appearance of C/2015V2 Johnson’s “anti-tail”. I imaged it under reasonable conditions from my home location on Saturday night 2017 May 27th. See my image here http://www.astromania.co.uk/2015V2_20170527_2329_PCarson.jpg
> It shows a fairly broad anti tail similar to some other recent images I’ve seen. However I’ve also seen a few good quality images from dark sites where the anti tail is very narrow and straight.
> Is the anti tail a gas tail or is it part of the dust tail we are viewing from a different angle or is it both?
> I imaged C/2015V2 the previous night with a different instrument and the tails had a similar appearance. See that image here http://www.astromania.co.uk/2015V2_20170526_0035_PCarson.jpg
> Whatever is causing its appearance it looks good.
> All the best
> Peter Carson
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