[BAA Comets] C/2012 X1 (LINEAR) worth keeping watch on

[Andrew Robertson]

Hi Richard,

I couldn't say for definite, it wasn't a scientific measurement just a
visual impression comparing two objects some distance apart with a couple of
mins between views. 2419 has a visual magnitude rating of m10.3 and on
reflection I would say the comet appeared a tad brighter but both objects
have different intensity gradients with 2419 having a fairy uniform
brightness across it's middle part with a fainter outer halo wheras X1
Linear had this bright central core with the halo fairly bright near the
core but getting progressively fainter towards it's edge - a very enjoyable
view when I wasn't expecting to see anything.  (I've just seen Jonathan's
e-mail quoting it's current magnitude as 9.)

Thanks for your comments and feedback, will try and get some more views but
that moon will be in the way in a few days.

Regards,

Andrew 

-----Original Message-----
From: comets-disc-bounces at britastro.org
[mailto:comets-disc-bounces at britastro.org] On Behalf Of Richard Miles
Sent: 12 December 2013 14:49
To: BAA Comets discussion list
Subject: [BAA Comets] C/2012 X1 (LINEAR) worth keeping watch on

Andrew Robertson wrote:

----- Original Message -----
From: "Andrew Robertson" <alphacentauri at tesco.net>
To: "'DENIS BUCZYNSKI'" <buczynski8166 at btinternet.com>; "'BAA Comets
discussion list'" <comets-disc at britastro.org>
Sent: Thursday, December 12, 2013 11:14 AM
Subject: Re: [BAA Comets] C/2013 r1 inner coma hoods.

C/2012 X1 Linear. Has this brightened again? I wasn't expecting to see
anything. When I last looked at it about a month ago it was already dimming
considerably after it's outburst a couple of weeks ago, being very diffuse
and low Surface brightness. On this view it looked very similar to my memory
of NGC 2419, 'the Intergalactic Wanderer!' A similar size and similar
brightness so I made the comparison moving the scope to NGC 2419 and then
back to X1 Linear. Yes, similar brightness and size accepting they're quite
a distance apart in the sky so not side by side comparisons. The difference
being, the middle half or 2/3's of 2419 is brighter followed by a fainter
outer halo whereas X1 Linear had a stellar core which had the appearance of
illuminating the outer halo which got steadily fainter towards it's edge.
Very nice view and a reminder that it's always worth re-checking these
comets after they've diminished.

------------------------

Hi Andrew,

Does that put the total magnitude at 9?
See:
http://aerith.net/comet/catalog/2012X1/2012X1.html
Looks to fit O.K. if it is.

What is worth watching is the brightness of the core - so your comment is
especially interesting.

This object outburst by 5-6 mag on about 2013 October 18. Now depending on
the rotation period of the nucleus, we may see other mini-outbursts starting
in the way you describe.

I've seen an image* from Juanjo Gonzalez (J01) dated December 09.2 where the
nucleus (10" square) is mag 12.37.
On November 23.2 the nucleus was 12.51 (R. Naves, M. Campas, 213) On
November 08.2 it was 12.72 (E, Cortes, A06)

According to the MPC ephemeris the comet should be slowly brightening so
maybe what you see is predicted but it is still worth following. It will
gradually move to higher solar elongation but sinks slowly further south as
it does so. Well worth watching out for further activity over the next
couple of months.


Richard Miles

*
http://groups.yahoo.com/neo/groups/Observadores_cometas/attachments/45417336
6


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