[vsnet-alert 14585] Re: [AAVSO-DIS] PNV J18110375-2717276

[Rob Kaufman]

I have it in images going back to Sept 2010 but can't track it further back
because I was shooting at smaller image size and less resolution before
that.  Quite bright in Oct 2010.  As Seiichiro Kiyota says, it needs to be
tracked back further.  Last night (13.567 May 2012 UT) I made it out to be
around mag 13.0 unfiltered (DSLR) in a shot taken at 200mm.  Faint and
quite reddened.

Here is just a selection of my previous 'rough' images of this object
(cropped from 55mm widefields and resized x2) with DSS plate overlays on
the position.  While there is crowding and the shots lack high resolution,
with a limiting magnitude of around 12.5 the resolution is sufficient:
29 Sept 2010
http://i727.photobucket.com/albums/ww271/Rob_Kau/PNVJ18110375-271727629Sept2010overlay.jpg
25 Oct 2010
http://i727.photobucket.com/albums/ww271/Rob_Kau/PNVJ18110375-271727625Oct2010overlay.jpg
28 April 2011
http://i727.photobucket.com/albums/ww271/Rob_Kau/PNVJ18110375-271727628Apr2011overlay.jpg<http://i727.photobucket.com/albums/ww271/Rob_Kau/PNVJ18110375-271727613May2012overlay.jpg>
08 May 2011
http://i727.photobucket.com/albums/ww271/Rob_Kau/PNVJ18110375-27172768May2011overlay.jpg
27 October 2011
http://i727.photobucket.com/albums/ww271/Rob_Kau/PNVJ18110375-271727627Oct2011overlay.jpg
For reference, here's a 55mm shot from last night 13 May 2012, with little
or nothing registering at the position (outside the limiting magnitude of
~12.5):
http://i727.photobucket.com/albums/ww271/Rob_Kau/PNVJ18110375-271727613May2012overlay.jpg
I'm assuming this would be very strange behaviour if it is a nova - varying
by less than a magnitude for over a year as far as I can see, and maybe
considerably longer.

Cheers -

Rob Kaufman (KBJ)
Bright, Victoria, Australia


The spectrum appears to have been interpreted as a nova in late decline,
On Mon, May 14, 2012 at 10:40 PM, arne <arne at aavso.org> wrote:

> Another interesting possible nova event, deep in the heart of Sagittarius,
> but visible from the southern U.S. and the southern hemisphere.  The
> discovery was 2012-04-23 according to the CBAT transient objects
> confirmation page; description of images of it dating from February 19,
> 2011 are posted.  It appeared to peak around mag 10 and is around 13th now.
>
> This was observed on 2012-03-26 and 2012-03-27 by APASS. I've placed the V
> and i' images from 2012-03-27 at
> http://www.aavso.org/tmp3/**pnvj1811v.jpg<http://www.aavso.org/tmp3/pnvj1811v.jpg>
> http://www.aavso.org/tmp3/**pnvj1811i.jpg<http://www.aavso.org/tmp3/pnvj1811i.jpg>
> (these are 12x12arcmin sections of the bigger APASS images, with north up
> and east left.)
>
> Taichi Kato posts on the vsnet group that there are spectra of it,
> indicating it is highly reddened and currently in the nebular stage (so
> late-time).  I haven't seen where the spectra are posted.  The basic
> reported light curve and the fact that Mati Morel indicates a red SPM and
> 2MASS star near this location would normally imply that this is just a mira
> variable, so the spectra are really important.
>
> It is still bright, and probably worthy of continued monitoring, but be
> very careful of the crowding.  I'll have Elizabeth put out a special notice
> when she get into the office.
> Arne
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