dwarf nova

Alert Notice 445 - Request for monitoring of SS Cygni in support of European VLBI radio observations

August 19, 2011: Following their very successful multiwavelength observing campaign on the dwarf nova SS Cygni in 2010 April (see AAVSO Special Notices #204 and 206 and the related information page), Dr. James Miller-Jones (International Centre for Radio Astronomy Research, Curtin University, Perth, Western Australia) and colleagues have a follow-up multiwavelength campaign on SS Cyg scheduled.

Special Notice #245: Outburst of SV Ari

August 2, 2011:  SV Ari, a suspected WZ Sge star, has gone into outburst.  Rod Stubbings posted a 15.0 magnitude estimate on 110802.788 that has been confirmed by Gianluca Masi.  Gary Poyner says:

"Discovered by M & G Wolf on Heidelberg plates taken in November 1905 at mag 12.0p.  Kimpel & Jansch reported a possible sighting in September 1943, but this was not confirmed.  Nothing has been seen since."

Special Notice #239: Dwarf Nova in Pegasus (PNV J21095047+1348396)

May 31, 2011: IAU Central Bureau for Astronomical Telegrams Electronic Telegram CBET 2731 (Daniel W. E. Green, ed.) announces the discovery by K. Itagaki, Yamagata, Japan, of a dwarf nova in Pegasus (reported by H. Yamaoka, Kyushu University, Japan) on 2011 May 24.672 UT at unfiltered CCD magnitude ~11.5. Spectroscopy by Akira Arai, Koyama Astronomical Observatory, Kyoto Sangyo University, Japan, on 2011 May 25.67 UT, and by D. D. Balam, Dominion Astrophysical Observatory, National Research Council of Canada, M. L.

Alert Notice 434: Outburst of NSV 1436

March 30, 2011: The cataclysmic variable NSV 1436 has been discovered in outburst.  This is the first bright outburst of this star observed since 1948, and followup observations are strongly encouraged.  Little is known about the nature of NSV 1436, and observations may help shed light on whether the star is an infrequently outbursting normal dwarf nova, a WZ Sge star, or recurrent nova.

Special Notice #233: Bright outburst of the cataclysmic variable SDSS J133941.11+484727.5

February 7, 2011: The star SDSS J133941.11+484727.5 has been reported in outburst by Jeremy Shears (Bunbury, UK).  Shears reports this star at magnitude 10.4 on 2011 February 7.919 (JD 2455600.419).  This is approximately 7 magnitudes above quiescence, which suggests a superoutburst of an SU UMa star or a WZ Sge-like outburst.  Gary Poyner (Birmingham, UK) confirms this outburst, estimating the star at 10.5 on February 7.959 (2455600.459).

Special Notice #221: Infrequent Outburst of the SU UMa Variable HT Cas

November 2, 2010: As reported by Tim Parson (Circle Pines, Minnesota, USA) and confirmed by Pavol Dubovsky (Kolonica, Slovakia), the infrequently-outbursting dwarf nova HT Cas is in outburst.  Parson observed HT Cas in outburst at m(vis)=12.9 on JD 2455502.93 (2010 November 2.43), and the outburst was confirmed by Dubovsky at m(vis)=12.4 on JD 2455503.3 (2010 November 2.8).  The last confirmed well-observed outburst of this star occurred on 2008 January 10.  Observations of this variable are strongly encouraged at this time.  Both visual and CCD observations are en