[vsnet-outburst 3036] TK4 : was there an outburst ?

["Tonny Vanmunster" <Tonny.Vanmunster@advalvas.be>]

Dear colleagues,

I just finished analysing an unfiltered CCD session of TK4, that was
obtained at CBA Belgium Observatory on 2001, November 1/2, between 17h00m UT
and 18h01m UT (i.e. Nov 1.708 and Nov 1.750 UT). I used a 0.35-m f/6.3
reflector and SBIG ST-7 CCD. The run was made following the outburst
announcement by Chris Jones, reported in vsnet-outburst 3022.

Based on my analysis, I have to conclude that the object *definitely* was
not visible during my observing interval, down to magnitude 18.0. Given the
(almost) overlap with Maciej's and Gary's observations, I'm inclined to
believe that both observers must have made an error in their identification
of TK4 (sorry, guys). If the object would have been around mag 14 between
Nov 1.683 and Nov 1.799, it should have been clearly visible on my
exposures. As I already said, there's no object brighter than mag 18.0 on
the location of TK4.

By the way, the reason for already interrupting the observing session after
1 hour, was exactly because I couldn't positively identify the variable.

I have put a "stacked" CCD image (10 x 30 sec exposure) showing the TK4
region on my Web site, for those of you interested in further exploring the
region.

By the way : I have also added a series of images taken this evening (Nov
3rd), showing the spectacular occultation of Saturn by the Moon, nicely
visible from Belgium.

Best regards,
Tonny Vanmunster
CBA Belgium Observatory
http://vsnet.lunarpages.com/cbabelgium
email : Tonny.Vanmunster@advalvas.be



YYYYMMDD(UT)   mag  observer
  20011018.128  <146  (Mike Simonsen)
  20011018.818  <154  (Christopher P. Jones)
  20011019.915  <146  (Mike Simonsen)
  20011021.897  <146  (Mike Simonsen)
  20011026.931  <145  (Maciej Reszelski)
  20011029.058  <146  (Mike Simonsen)
  20011031.813   140  (Christopher P. Jones)
  20011031.865   141  (Christopher P. Jones)
  20011101.683   139  (Maciej Reszelski)
  20011101.799   144  (Gary Poyner)     <=========
  20011101.815  <160C (Jochen Pietz) <=========
  20011101.821  <165C (Jochen Pietz)

> -----Original Message-----
> From: owner-vsnet-outburst@kusastro.kyoto-u.ac.jp
> [mailto:owner-vsnet-outburst@kusastro.kyoto-u.ac.jp]On Behalf Of Taichi
> Kato
> Sent: Saturday 3 November 2001 9:49 AM
> To: vsnet-alert@kusastro.kyoto-u.ac.jp;
> vsnet-campaign-dn@kusastro.kyoto-u.ac.jp;
> vsnet-outburst@kusastro.kyoto-u.ac.jp
> Subject: [vsnet-outburst 3033] TK4 quickly faded!
>
>
> TK4 quickly faded!
>
> Dear Colleagues,
>
>     The CCD run at Kyoto (M. Uemura and R. Ishioka) on Nov. 2 indicates
> that the object had already faded (if the reported outburst was a real
> one).  Although precise measurement of the magnitude should require
> further analysis, the object may have faded by more than 2-3 mag since
> the last visual sightings on Nov. 1.  Such a rapid fading is totally
> unexpected, and we encourage further intensive observations of this
> object.
>
> Regards,
> Taichi Kato
> VSNET Collaboration team
>
>

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