BELGIAN ASTRONOMICAL SOCIETY V.V.S. - Working Group Variable Stars Cataclysmic Variables Circular No.140 1997, May 23 Ed.: T. Vanmunster, Walhostraat 1A, 3401 Landen, BELGIUM Internet: tvanmuns@innet.be TEL. 32-11-831504 CVC Web Page : http://www.astro.columbia.edu/~cba/cvc =================================================================== V844 Her = Var43 Her [UGSU, 12.5p - 17.5p] ========================================== Robert Modic, USA reports his visual detection of an outburst of this poorly studied CVAP object. Confirmations have been received from Timo Kinnunen, Finland and Tonny Vanmunster, CBA Belgium. Available observations : 1997 May 20.340 UT, <15.3 (Modic, 0.5-m refl.); May 21.319 UT, 13.1 (Modic); May 22.368 UT, 13.2 (Modic) May 22.93 UT, 13.5 (Kinnunen, 0.44-m refl.); May 23.138 UT, 13.1 (Modic) May 23.364 UT, 13.4 (Modic) May 23.892 UT, 13.6 (T. Vanmunster, 0.25-m SCT + unfilt. CCD); V844 Her was last seen in outburst on October 7, 1996 by Ch. Scovil, who detected it photograpically at mag. 12.2. The object has been discovered by Antipin (IBVS 4360). It is located at R.A. = 16h25m01s.7 and Decl. = +39d09'26" (J2000.0). Antipin noted that the duration of the best observed outburst was between 12 and 18 days. Unfiltered time-series CCD photometry of V844 Her at the CBA Belgium Observatory on October 13/14, 1996 showed the existence of weak superhumps with a mean amplitude of approx. 0.14 mag. This established V844 Her as a new member of the UGSU-type dwarf novae. Unfortunately, the extreme short observing window at that moment did not allow the determination of an accurate superhump period value. Perhaps the current outburst presents another opportunity ? V1028 Cyg [UGSU, 13.0p - 18p] ============================= Gene Hanson, Az has reported his visual detection of an outburst of this very interesting SU UMa-type dwarf nova. No confirmative obser- vations have been reported. Although V1028 Cyg now has returned to quiescence, we strongly advise to follow-up this object, since this might have been a normal outburst triggering a superoutburst (see below for historical examples). 1997 May 17.440 UT, 14.2 (G. Hanson, 0.46-m refl.); May 17.451 UT, 14.1 (G. Hanson); May 17.469 UT, 14.1 (G. Hanson); May 18.427 UT, 14.6 (G. Hanson); May 18.466 UT, 14.7: (G. Hanson); May 19.409 UT, <15.1 (G. Hanson); May 19.465 UT, <15.6 (G. Hanson); May 19.994 UT, <14.5 (G. Poyner, 0.40-m refl.); V1028 Cyg was last seen in outburst on August 7, 1996 by M. Bies- mans and J. Pietz [CVC 102], when it reached mag. 13.5. This was a short outburst and the object faded rapidly, but 4 nights later it rebrightened again [CVC 103] and this became a superoutburst, that lasted 11 days. Independent superhump observations were reported by Ouda Station and by CBA Belgium [CVC 105]. A full photometric summary of the August 1996 superoutburst is given in CVC 107. During the July 1995 superoutburst of V1028 Cyg [CVC 48], the object became as bright as magnitude 12.7 [CVC 51, CVC 52], and the Ouda team of Kyoto University, Japan, was the first to succeed in detecting superhumps. We refer to CVC 51 for a full account of the reported superhumps and their evolution over time. Additionally, the star showed a post-outburst brightening [CVC 53], a phenomenon which should be looked for during the present outburst as well. VW CrB = Var21 CrB [UGSU, 14.5 - <17.5p] ======================================== Following the announcements in CVC 137 and CVC 139, this object has been monitored rather intensively by CCD photometry. The table below lists available observations. 1997 May 07.890 UT, <17.2 (L. Jensen, 0.25-m SCT, unfilt. CCD); May 09.030 UT, <16.0 (G. Poyner, 0.40-m refl., visual); May 09.880 UT, 14.1 (T. Vanmunster, 0.25-m SCT, unfilt. CCD); May 11.037 UT, 14.4 (Poyner); May 11.976 UT, 14.5 (Poyner); May 12.908 UT, 14.6 (Poyner); May 12.953 UT, 14.05 (Jensen); May 13.028 UT, 14.15 (Jensen); May 13.885 UT, 14.32 (Jensen); May 13.936 UT, 14.6 (Poyner); May 13.96 UT, 14.5 (T. Kinnunen, visual); May 14.972 UT, 14.7 (Poyner) May 15.882 UT, 14.49 (Jensen); May 16.889 UT, 14.58 (Jensen); May 19.960 UT, <14.8 (Poyner) CVC ONLINE AVAILABLE ==================== We are very pleased to announce that all CVC circulars (Nbr. 1 - Nbr. 139) are now online accessible through the CBA Web site. We furthermore have included a primary index page, which presents a tabular overview of all circulars, allowing fast retrieval of information about a particular object. Special thanks to Jonathan Kemp, Columbia University, New York for his efforts in setting up the CVC Web site, which may be accessed at following URL : http://www.astro.columbia.edu/~cba/cvc EDITORIAL ABSENCE ----------------- Please note that I will be absent between May 27 and May 29, 1997, due to participation in the 86th AAVSO Spring Meeting at Sion, Switzerland. I will furthermore be absent between June 7 and June 13, 1997, this time for participating in the 190th Meeting of the American Astronomical Society (AAS) at Winston-Salem, NC, USA. At both occasions, I will present the Center for Backyard Astro- phycis, its research on Cataclysmic Variables and specific results of the DV UMa campaign. I'd like to use this opportunity to thank the AAVSO, the CBA and Sky Publishing Corporation for their support. Tonny Vanmunster