[vsnet-outburst 6640] (fwd) Re: VSNET Weekly Campaign Summary - quiescent counterpart of OT_J195951.3+224232

[Taichi Kato]

(fwd) Re: VSNET Weekly Campaign Summary - quiescent counterpart of OT_J195951.3+224232

   From the attached chronology in response to Uemura-san's summary,
the actual maximum was well before the initial confirmation of superhumps.
The situation and the inferred outburst amplitude reminds me of V592 Her
(originally referred to as a nova, then potential X-ray transient/recurrent
nova, finally a WZ Sge-type star).  The initial stage with potential
early superhumps may have been overlooked.

   I give a reference to the V592 Her article.  Make a comparison with
the light curve:

   Kato et al. (2002) PASJ 54, 999 (perhaps publicly available as an astro-ph
preprint form).

   The early-stage rapid decline (as compared to other SU UMa stars) is
considered to reflect viscous depletion of a large amount of stored gas,
which results in a power-law type light curve, rather than usual exponential
(linear in magnitude scale) decline.  This feature in WZ Sge stars has
frequently been confused with "fast" classical novae when spectroscopy or
superhump detection was absent.

===

Dear Uemura-san

Actually there is probably not a 100% identification of the progenitor =
yet.
But it should be well above 90%.=20

At the position of the new object there is a faint fuzzy that its barrly =
above
the background in Arne's 26 magR USNO image:
http://www.aavso.org/tmp2/m27r.jpg
But there is also a color image by Joe and Gail Metcalf/Adam Block/
NOAO/AURA/NSF at:
http://www.noao.edu/outreach/aop/observers/m27.html
http://www.noao.edu/outreach/aop/observers/m27metcalf.jpg
that goes as deep as Arne's image and that shows it too.

R Jay GaBanny made a mouse-over animation of these two images
with his 20" RCOS image of the new object in outburst. So you can
take a look and judge it yourself at:
http://www.cosmotography.com/images/position_m27_nova.html
Also enjoy the nice surrounding of the new object at:
http://www.cosmotography.com/images/m27_nova-final.html


Arne and I gave lower limits for the outburst amplitude.
Arne assumed (<=3D 26 mag) - 16 mag =3D (>=3D 10 mag) according to the
And I assumed (<=3D 26 mag) - 15 mag =3D (>=3D 11 mag) as I've seen some
of the CCD measurement on the page of Hans-G=F6ran Lindberg.

If the above fuzzy is the progenitor and the below CCD measurements
are correct, the premilary outburst amplitude would be about:
26 magR (+-0.5 mag) - 14.5 magR (+-0.4 mag) =3D 11.5 magR (+-0.6 mag).


Hans-G=F6ran Lindberg has collected some amateur CCD images on
his page at:
http://sabbe.fragzone.se/KPO/05081827.htm
There he list two images dated Aug 14. and 15. measured at 14.5 mag.
His premilary measurements (that aren't submitted to the AAVSO and
vsnet yet) are shown in:
http://sabbe.fragzone.se/KPO/05081827-filer/image023.jpg


Here is what Hans-G=F6ran Lindberg, J=F6rg Hanisch and I found up to =
now:

* No previous outbursts.

* Last negative observations:
  - 2005-08-12  04:15 UT (Fred Lehman, Don Ellington)
    Limiting magnitude 19.2 CR
  - 2005-08-12  04:55 UT (Michael Fulbright)
    (no image receiced yet)

* First positive detections (found up to now):
  - 2005-08-14  Torben Taustrup and Flemming Ovesen from
    =C5rhus,Denmark (no time and mag available yet, but around
    14.5 magR by own vis. inspection)
    Limiting magnitude 17.6 CR
    http://tocobs.org/12prem/colour/m27-nova.jpg
  - 2005-08-15  00:20 UT (Ian King)   14.5 mag
    Limiting magnitude 19.0 CR
    http://www.ianking.darkhorizons.org/m27IM809lowres.htm
    http://www.ianking.darkhorizons.org/m27lrgb4.jpg
  - 2005-08-15  21:11 UT (Emilio Vismara)   14.5: mag
    Limiting magnitude 16.5: CR
    =
http://groups.yahoo.com/group/starlightxpress/files/Evism/M27_500mmf8.jpg=

  - 2005-8-16  04:30 UT  (Michael Fulbright)   15.1 mag CR
    (by own vis. inspection)
    Limiting magnitude 19.0 CR
    http://msfastro.net/AstroAlbum2/m27_hires_LHaRGB_081505_v4/
  - 2005-08-16  04:35 UT (Fred Lehman, Don Ellington)
    Limiting magnitude 17.6 CR
    (private communication, no mags set available)

Clear skies
  Wolfgang

--=20
Wolfgang Renz, Karlsruhe, Germany
Rz.BAV =3D WRe.vsnet =3D RWG.AAVSO