BELGIAN ASTRONOMICAL SOCIETY V.V.S. - Working Group Variable Stars Cataclysmic Variables Circular No.52 1995, August 15 Ed.: T. Vanmunster, Walhostraat 1A, 3401 Landen, BELGIUM Internet: tvanmuns@innet.be TEL. 32-11-831504 P. Van Cauteren, de Borrekenslaan 54, 2630 Aartselaar, BELGIUM Internet: pvancaut@innet.be TEL. 32-3-8774098 =================================================================== GO Com [UGWZ:, 13.1p - 20p] =========================== Daisaku Nogami and Taichi Kato, Ouda Team, Kyoto University, Japan report another outburst (or brightening) of this most intriguing object: "The current magnitude estimated from CCD images is 15-15.5 on Aug. 13.44 UT." This is the third reported outburst of GO Com in less than one month. As far as we understand, this behaviour has never been observed before in any cataclysmic variable. One may wonder what the physical processes are that are at the basis of this most uncommon behaviour. Taichi Kato and the Ouda Team also comment on the possible existence of superhumps in their observations : "The rate of decline of GO Com (~0.1 mag/day) seems to be characteristic to a superoutburst. Although very preliminary, Aug. 3 data seem to suggest the existence of variations of ~0.1 mag. A broad maximum possibly occurred around Aug. 3.473 UT (super- hump?), but is not conclusive because of the short duration (~40min) of the observing run and the bright sky background." The photometric summary below lists all observations of GO Com that we received, covering the three reported outbursts ! ----------------------------------------------------------------------- DATE (UT) MAGN MS SEQ OBSERVER REMARKS SOURCE ----------------------------------------------------------------------- 1995 07 16.951 13.3 mv GSC Vanmunster, T. 35-cm refl. CVC 47 1995 07 18.509 [13.6 mv Moriyama, M. 33-cm refl. VSNET 1995 07 18.908 [13.5 mv Schmeer, P. 20-cm SCT priv(SCH) 1995 07 19.917 [13.4 mv Schmeer, P. 20-cm SCT priv(SCH) 1995 07 19.928 [13.5 mv GSC Vanmunster, T. 35-cm refl. CVC 47 1995 07 20.921 [13.5 mv GSC Vanmunster, T. 35-cm refl. CVC 47 1995 07 21.87 [15.2 mv GSC Fidrich, R. 45-cm refl. priv(FID) 1995 07 21.87 [15.2 mv GSC Bakos, G. 45-cm refl. priv(FID) 1995 07 22.88 [15.2 mv GSC Fidrich, R. 45-cm refl. priv(FID) 1995 07 22.88 [15.2 mv GSC Bakos, G. 45-cm refl. priv(FID) 1995 07 22.923 [14.4 mv GSC Vanmunster, T. 35-cm refl. VVS 1995 07 25.481 [15.0 CU Iida, M. 16-cm+ST-6 VSNET 1995 07 25.483 16.6 CV Kato, T. 60-cm+ST-6 VSNET 1995 07 27.840 [14.4 mv GSC Fidrich, R. 45-cm refl. VSNET 1995 07 27.910 [14.4 mv GSC Szabo, R. 45-cm refl. VSNET 1995 07 30.845 13.3 mv GSC Szentasko, L. 33-cm refl. VSNET 1995 07 31.445 13.6 CV GSC Kato, T. 60-cm refl. VSNET 1995 07 31.8 13.2 mv GSC *Szentasko, L. 33-cm refl. VSNET 1995 08 01.447 13.5 CV GSC Kato, T. 60-cm refl. VSNET 1995 08 01.8 13.4: mv GSC *Szentasko, L. 33-cm refl. VSNET 1995 08 01.895 13.4 mv GSC Vanmunster, T. 35-cm refl. VVS 1995 08 02.8 13.5 mv GSC *Szentasko, L. 33-cm refl. VSNET 1995 08 03.467 13.8 CV GSC *Kato, T. 60-cm refl. VSNET 1995 08 03.8 13.9 mv GSC *Szentasko, L. 33-cm refl. VSNET 1995 08 04.459 13.9 CV GSC *Kato, T. 60-cm refl. VSNET 1995 08 04.8 [13.2 mv GSC *Szentasko, L. 33-cm refl. VSNET 1995 08 05.457 14.3 CV GSC *Kato, T. 60-cm refl. VSNET 1995 08 05.465 13.8 CU GSC *Iida, M. 16-cm+ST-6 VSNET 1995 08 06.457 15.1 CV GSC *Kato, T. 60-cm refl. VSNET 1995 08 07.452 16.5 CV GSC *Kato, T. 60-cm refl. VSNET 1995 08 13.44 15: CV GSC *Kato, T. 60-cm refl. VSNET TW Tri [UGZ, 13.3p - 17.0p] =========================== Ronald Downes, Space Telescope Science Institute, Maryland, emails : "In regard to CVC 50 on TW Tri, I can provide some more information. First, the classification as a Z Cam is not secure, although the CV classification does seem to be. There is a published spectrum by Zwitter and Munari in A. & A. Suppl. 107, 503, 1994, which shows strong Balmer emission. As for the coordinates, I have remeasured TW Tri, and get the following offsets from the published position: RA = 0.05s W, Dec = 0.9" N." Taichi Kato, Ouda Observatory, Kyoto University, Japan communicates : "TW Tri was discovered by Kurochkin (Astron. Trisk. No. 1023 (1978), TW Tri = SVS 2288). The author gave a finding chart and list of observa- tions. He commented that a typical outburst cycle length is 28 days. I could not find documentation about the existence of standstills. This object has been included in the targets of VSOLJ (Variable Star Observers League Japan) probably since 1987. A number of outbursts have been reported, including more recent one(s) reported on VSNET (last year?)." Taichi Kato and his team members finally also found outburst images of TW Tri,dating from July 27, 1995, when the outburst apparently had not yet fully developed. The photometric summary below lists some additional observations of the present outburst. Unfortunately, the declining phase has not been covered very well (due to interference from the full moon). ----------------------------------------------------------------------- DATE (UT) MAGN MS SEQ OBSERVER REMARKS SOURCE ----------------------------------------------------------------------- 1995 08 05.066 13.8 mv GSC *Vanmunster, T. 35-cm refl. VVS 1995 08 06.045 13.8 mv GSC *Vanmunster, T. 35-cm refl. VVS 1995 08 06.079 13.7 mv GSC *Broens, E. 35-cm refl. priv(BRO) V1028 Cyg [UGSS, 13.0p - 18p] ============================= Hajime Baba and Taichi Kato, Ouda team, Kyoto University, Japan, communicate: "Our CCD observations of Aug. 9 show that the superhumps of V1028 Cyg seem to have grown up again. The lightcurve of this object shows an amplitude on Aug. 9 of about 0.15 mag. in V band, although it was less than 0.05 mag. on Aug. 8. We have never encountered such a curious beha- viour before. We are interested in the physical process that happens in this system, which we will follow from now on." Additional observations of the present outburst (see also CVC 51) : ----------------------------------------------------------------------- DATE (UT) MAGN MS SEQ OBSERVER REMARKS SOURCE ----------------------------------------------------------------------- 1995 07 30.9 13.0 mv AA *Szentasko, L. 33-cm refl. VSNET 1995 08 01.9 13.0 mv AA *Szentasko, L. 33-cm refl. VSNET 1995 08 01.906 12.9 mv KA *Pietz, J. 40-cm refl. VSNET 1995 08 01.926 12.9 mv AA *Diepvens, A. 15-cm refr. VVS 1995 08 02.891 12.7 mv AA *Diepvens, A. 15-cm refr. VVS 1995 08 02.899 13.3 mv KA *Pietz, J. 40-cm refl. VSNET 1995 08 02.9 13.5 mv AA *Szentasko, L. 33-cm refl. VSNET 1995 08 02.903 12.7 mv GSC *Broens, E. 35-cm refl. priv(BRO) 1995 08 03.014 13.2 mv *Poyner, G. 40-cm refl. VSNET 1995 08 03.240 13.1: mv AA *Dillon, W. 28-cm SCT VSNET 1995 08 03.9 13.9 mv AA *Szentasko, L. 33-cm refl. VSNET 1995 08 04.876 13.6 mv KA *Pietz, J. 40-cm refl. VSNET 1995 08 04.890 13.0 mv AA *Diepvens, A. 15-cm refr. VVS 1995 08 04.9 13.8 mv AA *Szentasko, L. 33-cm refl. VSNET 1995 08 04.903 13.7 mv *Poyner, G. 40-cm refl. VSNET 1995 08 04.970 12.9 mv GSC *Broens, E. 35-cm refl. priv(BRO) 1995 08 05.050 13.6 mv AA *Vanmunster, T. 35-cm refl. VVS 1995 08 05.057 13.5 mv KA *Pietz, J. 40-cm refl. VSNET 1995 08 05.058 13.9 mv AA *Biesmans, M. 28-cm SCT priv(BIE) 1995 08 05.874 14.0 mv KA *Pietz, J. 40-cm refl. VSNET 1995 08 05.9 13.5 mv AA *Szentasko, L. 33-cm refl. VSNET 1995 08 05.910 13.8 mv *Poyner, G. 40-cm refl. VSNET 1995 08 05.956 13.9 mv AA *Diepvens, A. 15-cm refr. VVS 1995 08 05.984 13.9 mv KA *Pietz, J. 40-cm refl. VSNET 1995 08 06.028 13.7 mv AA *Vanmunster, T. 35-cm refl. VVS 1995 08 06.034 13.6 mv GSC *Broens, E. 35-cm refl. priv(BRO) 1995 08 07.537 15.1 CU *Iida, M. 16-cm+ST-6 VSNET 1995 08 08.906 14.1 mv *Poyner, G. 40-cm refl. VSNET 1995 08 10.997 [14.0 mv GSC *Poyner, G. 40-cm refl. VSNET FX Cep [UGSS?, 15.0p - 17.5p] ============================= The outburst of FX Cep has been very well monitored by several observers, yielding a detailed lightcurve. The photometric summary below (complemen- tary to the one published in CVC 51) concludes the observations of the present outburst. ----------------------------------------------------------------------- DATE (UT) MAGN MS SEQ OBSERVER REMARKS SOURCE ----------------------------------------------------------------------- 1995 08 01.952 14.6 mv GSC *Broens, E. 35-cm refl. priv(BRO) 1995 08 02.010 14.8 mv KA *Biesmans, M. 28-cm SCT priv(BIE) 1995 08 02.927 14.8 mv GSC *Poyner, G. 40-cm refl. VSNET 1995 08 02.934 14.7 mv GSC *Broens, E. 35-cm refl. priv(BRO) 1995 08 02.988 15.0 mv *Pietz, J. 40-cm refl. VSNET 1995 08 03.032 14.8 mv KA *Biesmans, M. 28-cm SCT priv(BIE) 1995 08 04.051 15.1: mv KA *Biesmans, M. 28-cm SCT priv(BIE) 1995 08 04.916 [15.0: mv *Pietz, J. 40-cm refl. VSNET 1995 08 04.963 14.9 mv GSC *Poyner, G. 40-cm refl. VSNET 1995 08 05.007 15.2 mv KA *Biesmans, M. 28-cm SCT priv(BIE) 1995 08 05.022 14.7 mv GSC *Broens, E. 35-cm refl. priv(BRO) 1995 08 05.097 14.9 mv GSC *Vanmunster, T. 35-cm refl. VVS 1995 08 05.934 15.0 mv GSC *Poyner, G. 40-cm refl. VSNET 1995 08 06.069 15.2: mv GSC *Vanmunster, T. 35-cm refl. VVS 1995 08 06.085 [14.6 mv GSC *Broens, E. 35-cm refl. priv(BRO) 1995 08 08.942 [14.5 mv GSC *Poyner, G. 40-cm refl. VSNET 1995 08 10.972 [14.5 mv GSC *Poyner, G. 40-cm refl. VSNET Tonny Vanmunster