BELGIAN ASTRONOMICAL SOCIETY V.V.S. - Working Group Variable Stars Cataclysmic Variables Circular No.93 1996, May 07 Ed.: T. Vanmunster, Walhostraat 1A, 3401 Landen, BELGIUM Internet: tvanmuns@innet.be TEL. 32-11-831504 -------------------------------------------------------------- The CATACLYSMIC VARIABLES Home Page: http://www.cv.psi.edu =================================================================== AK Cnc [UGSU, 13p - <17p] ========================= Gary Poyner, Birmingham, UK has informed us that Bill Worraker, Didcot, UK has detected an outburst of this UGSU-type dwarf nova, which is on the "Recurrent Objects Programme" of the TA/BAAVSS. In addition, the outburst has independently been reported by T. Burrows, USA (AAVSO News Flash No. 17). Available observations : 1996 May 02.202 UT, [13.6 (T. Burrows, USA, AAVSO NF 17); May 04.201 UT, 13.6 (T. Burrows); May 05.191 UT, 13.4 (T. Burrows); May 05.920 UT, 13.3 (B. Worraker, 0.26-m refl.); May 06.204 UT, 13.6 (T. Burrows); In vsnet-alert 405, Nick James, UK communicates accurate astrometric observations, based on CCD images obtained with a 0.30-m reflector : "The position for this variable is incorrect in Downes and Shara. I obtain the following J2000 position using 12 GSC stars of mean residual 0".24 in RA and 0".22 in Dec: 08h55m21s.20 +11d18'14".7 [J2000]." AK Cnc was last seen in outburst on January 24, 1996 by Watanabe, Japan (unconfirmed observation), at mag. 13.9. The last confirmed outburst was seen on Oct. 5, 1995 by B. Worraker [CVC 61]. In a recent publication (in A&A) on the March 1995 superoutburst of AK Cnc, R.E. Mennickent et al. report superhump observations with an amplitude of 0.2 mag (which appeared 4 days after maximum) and a period of 0.06749 d. From this result, they derived a likely orbital period of 0.065 d, a mass ratio (M2/M1) of 0.21 and a distance of 325 parsecs. They furthermore report an average cyclelength of 47 days. SW UMa [UGSU/DQ, 10.6v - 16.5v] =============================== The superoutburst of this variable is over now and has been extremely well covered. The photometric summary below is a compilation of all observations we received (over 150). It includes estimates of Poyner, Jensen, Midtskogen, Zissell, Hanson, Harvan, Moeller, Takahashi, Kato, Ouimet, Gunther, Schmeer, Biesmans, Comello, Broens, Gubbels, Diepvens, Burrows, Verdenet, Westlund, Skalak, Royer, Novak, Vanmunster, Fidrich, Watanabe, Itoh, Makiguchi, Kiyota, Nishimura. We are especially grateful to R. Novak, Copernicus Observatory Brno, Hungary, and P. Ouimet, Observatoire G?aux, Canada for their CCD observations. R. Novak, Brno, Hungary reports : "CCD R-band photometry of SW UMa made on April 17/18 at Copernicus Observatory in Brno (Czech Republic) shows superhumps with a period P=0.05866 d and an amplitude of about 0.20 mag." Year M Day (UT) Mag (vis+CCD) ---- - -------- ------------- 1996 3 17.087 16.9 1996 3 18.296 16.2 1996 3 19.131 16.1 1996 3 31.135 16.4 1996 4 1.168 16.8 1996 4 3.145 16.0 1996 4 6.83 [13.3 1996 4 6.83 [13.3 1996 4 7.96 [12.1 1996 4 10.903 [14.7 1996 4 10.903 [14.7 1996 4 11.227 [13.9 1996 4 11.837 [12.4 1996 4 11.847 14.0 1996 4 11.847 14.0 1996 4 11.875 13.5 1996 4 11.875 13.5 1996 4 11.9 13.6 1996 4 11.955 11.7 1996 4 11.955 11.7 1996 4 11.969 11.4 1996 4 11.969 11.4 1996 4 12.112 10.5 1996 4 12.112 10.5 1996 4 12.597 9.7 1996 4 12.85 10.4 1996 4 13.04 10.5 1996 4 13.052 10.5 1996 4 13.112 10.1 1996 4 13.187 10.2 1996 4 13.194 9.7 1996 4 13.22 9.6 1996 4 13.234 9.8 1996 4 13.438 10.3 1996 4 13.496 10.1 1996 4 13.559 10.2 1996 4 13.593 9.9 1996 4 13.851 10.5 1996 4 13.851 10.5 1996 4 13.851 10.5 1996 4 13.885 10.8 1996 4 13.892 10.5 1996 4 13.911 10.7 1996 4 13.927 10.0 1996 4 13.969 10.3 1996 4 13.969 10.3 1996 4 13.982 10.4 1996 4 13.982 10.4 1996 4 13.991 10.3 1996 4 13.991 10.3 1996 4 13.992 10.5 1996 4 13.999 10.4 1996 4 13.999 10.4 1996 4 14.024 9.7 1996 4 14.05 12.5 1996 4 14.202 10.0 1996 4 14.225 10.6 1996 4 14.442 10.2 1996 4 14.825 10.3 1996 4 14.831 10.0 1996 4 14.856 10.0 1996 4 14.869 10.5 1996 4 14.87 10.6 1996 4 14.88 10.3 1996 4 14.88 10.3 1996 4 14.891 10.8 1996 4 14.899 10.0 1996 4 14.946 10.8 1996 4 15.007 10.8 1996 4 15.055 10.3 1996 4 15.13 10.6 1996 4 15.461 9.9 1996 4 15.833 10.3 1996 4 15.839 10.6 1996 4 15.847 10.3 1996 4 15.847 10.3 1996 4 15.88 10.5 1996 4 15.88 11.0 1996 4 15.88 10.5 1996 4 15.9 10.8 1996 4 15.95 10.6 1996 4 15.963 10.5 1996 4 16.83 10.4 1996 4 16.83 10.4 1996 4 16.842 10.4 1996 4 16.853 10.3 1996 4 16.856 11.3 1996 4 16.869 10.6 1996 4 16.891 10.9 1996 4 17.06 10.6 1996 4 17.06 10.6 1996 4 17.179 10.5 1996 4 17.468 10.5 1996 4 17.513 10.5 1996 4 17.8 10.5 1996 4 17.847 10.2 1996 4 17.867 10.5 1996 4 18.001 10.7 1996 4 18.042 10.6 1996 4 18.056 10.5 1996 4 18.059 11.0 1996 4 18.472 10.8 1996 4 18.488 10.5 1996 4 18.511 10.6 1996 4 18.542 11.1 1996 4 18.833 10.6 1996 4 18.858 11.0 1996 4 18.974 11.0 1996 4 19.85 11.2 1996 4 19.929 10.7 1996 4 20.562 11.1 1996 4 20.651 11.1 1996 4 20.8 11.4 1996 4 20.867 11.2 1996 4 21.031 11.3 1996 4 21.047 10.8 1996 4 21.528 11.7 1996 4 21.83 11.1 1996 4 21.831 11.6 1996 4 21.867 11.3 1996 4 21.883 11.3 1996 4 21.892 11.2 1996 4 22.036 11.0 1996 4 22.512 11.8 1996 4 22.831 11.5 1996 4 22.849 11.3 1996 4 23.449 11.2 1996 4 23.458 11.4 1996 4 24.521 11.5 1996 4 24.569 11.3 1996 4 24.661 12.1 1996 4 25.055 11.6 1996 4 25.861 11.8 1996 4 25.951 12.8 1996 4 26.85 11.5 1996 4 26.865 11.6 1996 4 26.881 11.7 1996 4 27.494 11.4 1996 4 27.917 11.7 1996 4 28.853 11.7 1996 4 29.863 12.6 1996 4 29.973 13.2 1996 4 30.985 14.9 1996 5 2.833 [12.3 1996 5 4.872 [13.5 1996 5 4.951 [14.7 1996 5 5.488 14.0 1996 5 5.527 [13.9 1996 5 5.528 [13.5 1996 5 5.556 13.5 1996 5 5.9 [14.5 1996 5 5.953 [14.3 Tonny Vanmunster