[BAA Comets] Sudden changes on C/2019 Y4 (ATLAS)

[Martin Smith]

The images did look odd doing the astrometry on ATLAS last night, I was
wondering if I had a problem with guiding on the comet. C/2017 T2 was nice
and round however, so presumably this is the actual shape of the thing.
Pictures from Astrometrica show the difference nicely.

[image: T2-120sec.jpg]
C/2017 T2 (PANSTARRS)

[image: Y4-120sec.jpg]
C/2019 Y4 (ATLAS)


On Tue, Apr 7, 2020 at 10:16 AM <twinklespinalot at gmail.com> wrote:

> As I stated on FB, if this comet has split up it could be very interesting
> to watch further, we could have another 73P/Schwassman-Wachmann on our hands
> Sent from my iPhone
>
> On 7 Apr 2020, at 02:35, Nick Haigh <happylimpet at hotmail.com> wrote:
>
> 
> Hi all, I took these images this evening with a 610 baader longpass (as
> full moon) coveing 6820secs of 10sec subs.
>
> Clearly show breakup of the nucleus - or at least several condensations,
> to be interpreted somehow!
>
> Image 6.2' wide - ive upsampled it 2x to make it clearer. Original
> resolution 0.72"/pixel, so ~1.44"/pix here.
>
> Cheers
>
> Nick
> ------------------------------
> *From:* Comets-disc <comets-disc-bounces at lists.britastro.org> on behalf
> of Nick James <ndj at nickdjames.com>
> *Sent:* 06 April 2020 21:26
> *To:* BAA Comets discussion list <comets-disc at britastro.org>
> *Subject:* Re: [BAA Comets] Sudden changes on C/2019 Y4 (ATLAS)
>
> As of this evening (April 6) my astrometry now shows a residual of 6
> arcsec in RA (approx in the direction of the tail). I've plotted the
> brightness profile of the comet in a slice through the nucleus and
> parallel to the tail for three dates, 2020 March 31, April 5 and April
> 6. The peak brightness is falling and the inner coma is broader in the
> tailward direction. All of this implies this comet may not last much
> longer. I hope I'm wrong but observe it while you can!
>
> Nick.
> <c2019y4-20200406-610-2_cropsc_itgauss_x2_arrow.jpg>
> <c2019y4-20200406-610-2_cropsc_itgauss_x2.jpg>
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