Outburst of GO Com

(vsnet-alert 714)

Visual magnitude estimates by P. Schmeer, Bischmisheim, Germany:

Feb.  6.11  UT, (14.2 ;  7.111,  14.0:;  7.194,  13.7
Sequence:   VSNET
Instrument: 203-mm SCT

Normal outbursts of GO Com are very short, so confirmation is urgently required.

(from CVC 128, also vsnet-alert 716)

GO Com [UGSU, 13.1 - 20.0p]

We have been informed by Patrick Schmeer, Germany of an outburst of GO Com, an object which is part of the TA/BAAVSS Recurrent Objects Programme. Confirmative observations were received from the AAVSO [News Flash No. 111].

1997 Feb 06.11  UT, [14.2  (P. Schmeer, 0.20-m SCT);
     Feb 07.111 UT,  14.0: (Schmeer);
     Feb 07.194 UT,  13.7  (Schmeer);
     Feb 07.212 UT,  13.8  (Stewart);
     Feb 07.317 UT,  14.15 (Zissell, CCD + V filter);
     Feb 07.378 UT,  14.15 (Zissell, CCD + V filter);

The previous outburst of GO Com was reported on 1996, Mar 26 by M. Iida, Japan [CVC 89], and was a faint, normal one [CVC 90]. GO Com underwent a very remarkable series of outbursts in July/August 1995. In less than one month, 3 separate outbursts were observed. What follows is a short review of the 1995 outburst behaviour :

- The first outburst of GO Com was detected on July 16, 1995 (T. Vanmun-
  ster) [CVC 47]. He estimated the object at mag. 13.3. Due to the low 
  altitute of GO Com at the moment of outburst detection, no confirmative 
  observations were received.

- Hungarian amateur Laszlo Szentasko detected the second outburst of GO 
  Com. His observation (mag. 13.3) was made on July 30, 1995 [CVC 51]. 

- It is still unclear how the exact relationship between het first and 
  second outburst of GO Com should be interpreted. Was the first outburst 
  a normal one, triggering the second (super?)outburst ? To make things 
  even more complicated, another outburst was reported, about two weeks 
  later. This third one was detected by Daisaku Nogami and Taichi Kato, 
  Ouda Team, Kyoto University, Japan on August 13, 1995 [CVC 52], when 
  they observed GO Com at mag. 15-15.5. It was a normal one. 

GO Com was discovered by Kowal as an eruptive object on a Palomar plate on 1977 July 1.213. Usher independently discovered a very blue star of B=18.1 during the survey of the north galactic pole region. This star (US 31) was identical to GO Com. Vogt and Bateson classified GO Com as a WZ Sge-type dwarf nova, because of its large outburst amplitude and low outburst frequency.

Tonny Vanmunster

GO Com paper

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