Re: V844 Her outburst Extracted from previous messages. Object of extreme importance. ============================================================================ Date: Mon, 30 Sep 1996 17:12:58 +0900 From: Taichi Kato <tkato@kusastro.kyoto-u.ac.jp> Subject: [vsnet 834] new UG star in Her Dear dwarf nova fans, According to IBVS No. 4360, Antipin discovered another new dwarf nova (bright!) in the eta Her field. Var43 16h 25m 01s.7 +39o 09' 26" (J2000.0) UG 12.5-17.5p Antipin reports that the duration of the best-observed outburst is between 12 and 18 days. Regards, Taichi Kato ============================================================================ From: c.scovil@genie.com Date: Sat, 12 Oct 96 07:52:00 GMT Subject: [vsnet-obs 4061] Observations - outburst V43 He Following Dr. Kato's notice of Antipin's V43 in Hercules I took a photo of the field on Oct. 7th at 1:34 UT. The variable was bright, at about 12.2 using Antipin's sequence, which I assume to be Photoelectric (V). Visual observation of the star Oct. 12 at 0.0 UT showed it at magnitude 14.3. Regards, C. Scovil, AAVSO ============================================================================ From: VANMUNSTER Tonny <tvm@lms.be> To: vsnet-obs@kusastro.kyoto-u.ac.jp (vsnet-obs) Date: Mon, 14 Oct 96 13:44:05 METDST Subject: [vsnet-obs 4075] Var43 Her : new UGSU-type dwarf nova Dear Colleagues, Unfiltered time-series CCD photometry of Var43 Her (*) at the Center for Backyard Astrophysics Belgium (CBA Observatory), using a 25-cm f/6.3 SCT telescope and ST-7 CCD, on October 13/14, 1996 shows the existence of weak superhumps with a mean amplitude of approx. 0.14 mag. This establishes Var43 Her as a new member of the UGSU-type dwarf novae. Determination of a superhump period value is extremely difficult due to the short observing window (photometry of Var43 Her in Belgium currently is restricted to approx. 1.5 hours). We therefore would like to request assistance from other observatories, so that multi-longitudinal coverage becomes possible. The present outburst of Var43 Her was first announced by Ch. Scovil (VSNET message), and detected on Oct. 7, 1996. The object is now fading and any attempts to study the superhumps should be made in the next couple of nights. Kind regards, Tonny Vanmunster CBA Belgium (*) Var43 Her was discovered by Antipin (IBVS 4360) and is located at R.A. = 16h25m01s.7, Decl = +39d09'26" (J2000.0). Magnitude range is 12.5 - 17.5p. ============================================================================ Date: Sat, 24 May 1997 07:35:55 +0900 (JST) From: Taichi Kato <tkato@kusastro.kyoto-u.ac.jp> Subject: [vsnet-alert 927] superoutburst of V844 Her = Var43 Her The recently discovered SU UMa-type dwarf nova, V844 Her = Var43 Her is undergoing a superoutburst as indicatied by the following observations. (Most magnitudes based on Antipin's photographic sequence; the true V-magnitude may be brighter by ~0.5 to 1.0 mag.) YYMMDD(UT) mag code 970519.964 <149 POY 970520.340 <153 MRV 970521.319 131 MRV 970522.367 132 MRV 970522.930 135 KNN 970523.137 131 MRV 970523.364 134 MRV The object was last reported to be in outburst in 1996 Oct., when Tonny Vanmunster detected superhumps, finally enabling an unambiguous classification of this object (cf. vsnet-obs 4075, http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-obs/msg04075.html). Regards, Taichi Kato ============================================================================ Date: Sat, 24 May 1997 19:21:16 +0200 (MET DST) From: Tonny Vanmunster <tvanmuns@innet.be> Subject: [vsnet-obs 5837] V844 Her in superoutburst. A story of bad luck. Dear colleagues, Last night I obtained over 4 hours of CCD photometry of Var43 Her = V844 Her. The resulting light curve clearly showed prominent super- humps, hence qualifying the present outburst again as a superoutburst. So far the good news ... But ... at the moment I launched the period determination programme, my hard disk crashed (hopefully without data loss). When I have my computer back in a few days, I hope to continue the period determination (without interrupts this time ?) and I will communicate the superhump period value. Regards, Tonny Vanmunster CBA Belgium ============================================================================ Date: Tue, 27 May 1997 10:28:49 +0900 (JST) From: Taichi Kato <tkato> Subject: [vsnet-alert 940] V844 Her: unique short orbital period SU UMa star V844 Her: unique short orbital period SU UMa star Recent reports [1,2] on V844 Her (=Var43 Her) confirm the star as being an SU UMa star having one of the shortest superhump periods. A table of short Psh SU UMa stars (taken from [3]; stars with (*) are newly added here): Psh Porb --------------------------------------------------------- V485 Cen 0.0421 0.041 (*) DI UMa 0.0555 V844 Her 0.056 +/- 0.001 (*) LL And 0.05700 WZ Sge 0.05714 0.05669 AL Com 0.0572 0.05666 SW UMa 0.0583 0.05681 HV Vir 0.05865 0.05799 WX Cet 0.05936 0.0582 RZ LMi 0.05946 T Leo 0.0602 0.05882 EG Cnc 0.06036 0.05821 Aside from V485 Cen, all of these short Psh SU UMa stars are either what is called WZ Sge-type dwarf novae and ER UMa-type (or RZ LMi-type) dwarf novae. The former category contains WZ Sge, AL Com, HV Vir, EG Cnc, and related members LL And, SW UMa, WX Cet and T Leo. The latter group contains DI UMa and RZ LMi. Which group will V844 Her belong to, or comprise by itself a unique class? From available photometric materials ([4] and reports to VSNET), bright (super) outbursts are separated by 220-230 days, without detectable normal outbursts (despite the brightness of the object) so far. Will it mean V844 Her is a WZ Sge-type dwarf nova with a supercycle length of 220-230 (!) days? Regards, Taichi Kato (please continue the discussion in vsnet-chat if necessary) References: [1] T. Vanmunster, CVC 141, or http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-alert/msg00935.html [2] L. T. Jensen [vsnet-obs 5854] http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-obs/msg05854.html [3] D. Nogami, S. Masuda, T. Kato 1997, PASP submitted [4] S. V. Antipin 1996, IBVS 4360 ============================================================================ Date: Sun, 1 Jun 1997 05:18:06 -0400 (EDT) From: Joe Patterson <jop@astro.columbia.edu> Subject: [vsnet-alert 953] V844 Her = Var43 Her V844 Herculis (= Var43 Her) continues to show strong superhumps during its current superoutburst. Merged coverage from 5 CBA stations shows a principal period of 0.05602+-0.00011 d during May 25-31. Very short. Very complex too: large wiggles in the O-C and variability in the waveform suggest the possibility of another signal closely spaced in period. Fourier analysis yields a second period at 0.05534+-0.00010 d, but this must be regarded with caution as power-spectrum structure can also be produced by mere amplitude changes (if strong enough). Second period or no, the star is of very high interest, and we earnestly seek help from other observers able to obtain time-series photometry, in order to produce the best sampling of this remarkable light curve. We expect to be watching the star throughout June. The CBA team, so far: Joe Patterson (New York) (jop@astro.columbia.edu, 802-425-5008) Tonny Vanmunster (Belgium) Lasse Jensen (Denmark) Dave Skillman (Maryland) Dave Harvey (Arizona-Tucson) Bob Fried (Arizona-Flagstaff) ============================================================================