[vsnet-alert 651] rebrightening of EG Cnc

[Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>]

from CVC 119 (VVS Belgium, also vsnet-obs 4678):
----------------------------------------------------------------------

EG Cnc [UGSU, 11.9v - 17:v]
===========================

Unfiltered CCD photometry by Tonny Vanmunster at the CBA Observatory, 
Belgium shows that EG Cnc is now having a second major post-outburst
rebrightening. The event has been confirmed visually by Gary Poyner,
Birmingham. Here are the observations :

1996 Dec 28.964 UT,  13.6  (T. Vanmunster, 0.25-m SCT, unfilt. CCD);
     Dec 28.969 UT,  13.6  (G. Poyner, 0.40-m refl., seq: VSNET);


We are now (Dec 29.0 UT) performing time-series CCD photometry on this 
object, which we hope to continue till about Dec 29.3 UT. It will be
extremely interesting to find out if superhumps are again appearing
and, if so, to determine the associated superhump period in this stage.

Remark that UZ Boo also showed a second post-outburst brightening
during its August 1994 outburst [CVC 16].

Other recent observations of EG Cnc are summarized in the table
below and complement the reports in previous CVC circulars.

-------------------------------------------
DATE (UT)       MAGN   MS  OBSERVER   
-------------------------------------------
1996 12 21.142   16.06 CV  Zissell
1996 12 21.950   13.6  mv  Poyner
1996 12 22.199   13.5  CV  Zissell
1996 12 22.773   14.10 CV  Ouda
1996 12 22.821   14.17 CV  Ouda
1996 12 22.91    13.6  mv  Kinnunen
1996 12 22.963   14.1  mv  Poyner
1996 12 23.067   14.1  mv  Poyner
1996 12 23.558   15.15 CV  Ouda
1996 12 23.851   14.9  mv  Itoh
1996 12 23.855   15.68 CV  Ouda
1996 12 24.563   16.16 CV  Ouda
1996 12 24.611  [15.6  mv  Koshiro
1996 12 24.864   15.77 CV  Ouda
1996 12 25.17   [15.1  mv  Kinnunen
1996 12 25.011   15.7  CU  Vanmunster
1996 12 25.595   15.20 CV  Ouda
1996 12 25.90    13.8? mv  Kinnunen
1996 12 25.958  [15.9  CU  Vanmunster
1996 12 25.987  [15.9  CU  Vanmunster
1996 12 26.611  [15.6  CV  Koshiro
1996 12 26.827   16.02 CV  Ouda
1996 12 27.747   16.04 CV  Ouda
1996 12 28.04   [15.9  CU  Vanmunster

Tonny Vanmunster

from CVC 120 (also vsnet-obs 4688)

The second major rebrightening of EG Cnc, announced yesterday in 
CVC 119, has been followed photometrically by Tonny Vanmunster
at the CBA Observatory, Belgium using a 0.25-m f/6.3 SC telescope
and ST-7 CCD. A period analysis of unfiltered observations during
a 3.5h run (Dec 28/29), using the PDM method, yields a superhump
period of 0.0584 +/- 0.0009 d, after heliocentric correction and
removal of a linear trend of decline. The mean semi-amplitude of 
the superhumps is 0.07 mag.

Further time-series photometry in this stage of the outburst is of 
utmost importance. 

----------------------------------------------------------------------
(end of inclusion)

    Note that the present period of 0.0584 d is very close to Matumoto's
period (0.0582 d) obtained during the earliest stage of the outburst
(IAUC No. 6517, vsnet-alert 607 and 613).  The latter being a good candidate
for the orbital period ("orbital superhumps"), the orbital signal may have
become predominant again in contrast to persistent superhump (period near
0.0603 d) signals governing the first post-outburst rebrightening.

Regards,
Taichi Kato

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