- vsnet-alert - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-alert 28173] CM Del faint state
by Pavol A. Dubovsky 26 May '26

26 May '26

UGZ/IW type variable CM Del entered the new faint state. See my recent visual records: DELCM 20260521.140 15.30 DPV DELCM 20260523.108 15.36 DPV DELCM 20260526.135 16.02 DPV Clear Skies! -- Pavol A. Dubovsky Variable Star Section, Slovak Astronomical Society and Slovak Union of Astronomers var.kozmos.sk www.bombol.space

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[vsnet-alert 28167] TCPJ15030519+2202041: early superhump and rapid decay
by Hiromasa Hoke 25 May '26

25 May '26

TCPJ15030519+2202041: shows early superhump and rapid decay now Itoh-san, Moriyama-san, Hiraga-san, Funada-san, Magnus Larsson, and Josch Hambsch have newly reported their observations. According to the data, this object showed an early superhump with an amplitude of 0.03. Furthermore, this object has a superhump period of 0.03041(1). Now, this object shows rapid fading since May 15. AM CVn-type dwarf novae show the second outburst after an interval of several to more than ten days. This is a perfect opportunity to observe the growing superhump, so it is very important to observe this object even if it gets faint. best regard, Hiromasa Hoke

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[vsnet-alert 28171] Outbursts 21/05/2026
by Rod Stubbings 23 May '26

23 May '26

Outbursts and selected activity. object YYMMDD(UT) mag code remarks AQLFO 260521.663 146 Stu.RASNZ outburst AQLPQ 260521.687 153 Stu.RASNZ outburst AQLV1047 260521.687 153 Stu.RASNZ outburst AQLV1885 260521.694 150 Stu.RASNZ outburst CAROQ 260521.537 144 Stu.RASNZ active CENNN 260521.637 154 Stu.RASNZ outburst CENV803 260521.664 130 Stu.RASNZ outburst CHAST 260521.542 143 Stu.RASNZ active CRABP 260521.571 150 Stu.RASNZ active CRTBF 260521.530 147 Stu.RASNZ outburst HYAV392 260521.528 148 Stu.RASNZ outburst HYIWX 260521.729 138 Stu.RASNZ outburst HYIDR 260521.728 151 Stu.RASNZ outburst INDTT 260521.649 128 Stu.RASNZ outburst MICCM 260521.653 146 Stu.RASNZ outburst NORHP 260521.567 132 Stu.RASNZ outburst NORIK 260521.568 144 Stu.RASNZ active PAVV548 260521.647 142 Stu.RASNZ outburst PSATY 260521.704 148 Stu.RASNZ active SCOV478 260521.475 151 Stu.RASNZ active SERUZ 260521.573 132 Stu.RASNZ active SGRV2276 260521.651 153 Stu.RASNZ outburst NSV 11274 260521.558 140 Stu.RASNZ active LMC V3434 260521.499 144 Stu.RASNZ outburst MASTER OT J142023.47-485540.0 260521.713 128 Stu.RASNZ outburst -- Rod Stubbings Tetoora Road Observatory Victoria, Australia Honorary Associate member Astronomical Society of Australia Telescope: "Infinity" 22" f/3.8 stubbo(a)dcsi.net.au http://rodstubbingsobservatory.wordpress.com/

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[vsnet-alert 28169] AT 2026nhs = TCP J17521907+5001155 in superoutburst
by Marc Deldem 22 May '26

22 May '26

TNS AT 2026nhs (https://www.wis-tns.org/object/2026nhs) is TCP J17521907+5001155 (https://vsx.aavso.org/index.php?view=detail.top&oid=285776) UGSU Type Observations (available on AAVSO database) last night 2026-05-21 to 2026-05-22 show a superoutburst. Marc Deldem

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[vsnet-alert 28166] 2026 outburst of TCP J05454551+5954307 = ASASSN-22dq (UGWZ)
by Kirill Sokolovsky 13 May '26

13 May '26

TCP J05454551+5954307 = ASASSN-22dq (UGWZ) was found in outburst on 2026-05-13.1420 UTC at unfiltered magnitude CV=14.65 in images obtained with the NMW-TexasTech survey (135mm telephoto lens + QHY600M CMOS camera). The images are available at http://tau.kirx.net/img/TCPJ05454551+5954307/ Nothing brighter than CV~15.4 is visible at this location in images obtained the previous night on 2026-05-12.1429 with the same camera. The previous outburst of TCP J05454551+5954307 (14.7mag) was discovered on 2022-03-19.46139 by Hideo Nishimura, Kakegawa, Shizuoka, Japan. Original TOCP page: http://www.cbat.eps.harvard.edu/unconf/followups/J05454551+5954307.html VSX record: https://vsx.aavso.org/index.php?view=detail.top&oid=2227062 ZTF lightcurve: https://ztf.snad.space/dr23/view/1816212100005173 ASAS-SN lightcurve: https://asas-sn.osu.edu/sky-patrol/coordinate/077b9ec9-61b5-4dba-9a47-fc49f… Best wishes, Kirill On Tue, 29 Mar 2022, Taichi Kato wrote: > TCP J05454551+5954307: ordinary superhumps > > Observations from Crimean Astrophys. Obs. indicate > that ordinary superhump evolved on Mar. 27. >

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[vsnet-alert 28165] TCP J07151825+4753167 and TCP J15030519+2202041: new hydrogen-rich and helium-rich WZ Sge-type dwarf novae
by Hiromasa Hoke 11 May '26

11 May '26

Dear all, We posted the photometric follow-up results by Itoh-san and Moriyama-san for TCP J15030519+2202041 and our spectroscopic follow-up results for TCP J15030519+2202041 and TCP J07151825+4753167 to ATel. https://www.astronomerstelegram.org/?read=17791 We concluded that J0715+4753 is a new WZ Sge-type dwarf nova because Hα has a narrow emission core and its spectrum shows a blue continuum with the Balmer and HeI absorption lines. J1503+2202 is a new AM CVn-type dwarf nova because this object has HeI absorption lines, a temperature of ~25,000K and possible early superhump period of 0.0303(1) d. Follow-up observations are important. Especially, TCPJ1503+2202 is a long-period AM CVn star, and the opportunity to observe such an event is rare. Continuous time-series observations are strongly encouraged. best regard, Hiromasa Hoke

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[vsnet-alert 28164] Quasar S5 1803+78, optical bright state
by Stefan Karge 04 May '26

04 May '26

Quasar S5 1803+78, optical bright state Object date, UTC mag comment ------------------------------------------------------------ QSO S5 1803+78 2026-04-15,070 14.36CV active, Tns.Obs., 90mm QSO S5 1803+78 2026-04-28,083 14.53V active, BGO, 60cm QSO S5 1803+78 2026-05-01,969 14.39V active, Tns.Obs., 31.5cm CDK ------------------------------------------------------------ Taunus Observatory, MPC B01, 31.5cm CDK (Tns.Obs) Taunus Observatory, MPC B01, 90mm Apo (Tns.Obs) Burke-Gaffney Observatory, 60cm CGT (BGO) Observer: Stefan Karge (SKA) http://quasar.square7.ch/fqm/1803+784.html End

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[vsnet-alert 28162] ATLAS26dqo: new WZ Sge-type dwarf nova
by tonny.vanmunster＠gmail.com 18 Apr '26

18 Apr '26

Dear colleagues, ATLAS26dqo (aka TCP J16163603+4452289) was discovered by the ATLAS survey (J. Tonry et al.) on 2026 Mar 31.5 at mag 18.8. The object subsequently reached a peak of mag 14.0. The quiescent counterpart is a 22.8 g mag star, implying an outburst amplitude of ~9 mag. I have completed the analysis of my unfiltered CCD time-series observations of ATLAS26dqo, obtained on 2026 Apr 14/15 (CBA Belgium Observatory), and Apr 15/16 (CBA Extremadura Observatory, Spain). The data were acquired under mostly clear skies with 0.40-m telescopes. Key findings: * Superhump evolution: the Apr 14/15 light curve shows the emergence of Stage A superhumps with an amplitude of 0.07 mag. By Apr 15/16, the system transitioned into fully developed Stage B common superhumps with an amplitude of 0.14 mag. Note that I observed this object on multiple nights before Apr 15/16, but no obvious modulations were seen. * Period analysis: using multiple methods (ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM via Peranso 3.1), I derive a combined superhump period of 0.0608 +/- 0.0004d for the night of Apr 15/16. * Magnitude: the object was measured at mag CV = 15.5 on Apr 15th. Conclusion: The extreme outburst amplitude (almost 9 mag) and the remarkably long delay (~15 days) between initial discovery and the onset of common superhumps strongly confirm that ATLAS26dqo is a new WZ Sge-type dwarf nova. Image calibration and photometry were carried out using Phoranso, which enabled simultaneous photometry of additional variable stars in the same field of view. Continued monitoring is strongly encouraged to study the superhump profile and evolution. I will submit my observations to AAVSO, CBA and VSNET for further analysis. With kind regards, Tonny --- Tonny Vanmunster CBA Belgium Observatory CBA Extremadura Observatory http://www.cbabelgium.co <http://www.cbabelgium.com/> m PERANSO : The Light Curve and Period Analysis Software http://www.peranso.co <http://www.peranso.com/> m PHORANSO: Photometric Reduction and Analysis Software http://www.phoranso.com <http://www.phoranso.com/>

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[vsnet-alert 28155] NSV 1440 outburst
by Rod Stubbings 13 Apr '26

13 Apr '26

The AM CVn-type object NSV 1440 is in a bright outburst. The last bright outburst was in 2021. NSV 1440 260404.433 132 Regards, Rod. -- Rod Stubbings Tetoora Road Observatory Victoria, Australia Honorary Associate member Astronomical Society of Australia Telescope: "Infinity" 22" f/3.8 stubbo(a)dcsi.net.au http://rodstubbingsobservatory.wordpress.com/

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[vsnet-alert 28160] ASASSN-26ck: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 07 Apr '26

07 Apr '26

Dear colleagues, ASASSN-26ck was discovered by the ASAS-SN team on 2026 Mar 26.3 at mag g = 14.6. The quiescent counterpart is a 21.9 g mag star or a ~23.5 mag star, implying an outburst amplitude of ~7 to 9 mag. I have just completed the analysis of my unfiltered CCD time-series observations of ASASSN-26ck, obtained on 2026 Apr 04/05 and 05/06 at CBA Extremadura Observatory, and Apr 06/07 at CBA Belgium Observatory. The CBA Belgium data were acquired under clear skies with a 0.40-m f/10.0 telescope and a QHY-268M CMOS camera. No obvious modulations were seen on the nights of Apr 04/05 and 05/06. However, the Apr 06/07 light curve clearly shows regular superhump modulations with an amplitude of 0.15 mag. A period analysis using ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0601 +/- 0.0014d. The object was measured at mag CV = 16.1 on Apr 06th. Image calibration and photometry were carried out using the latest release of Phoranso, which enabled simultaneous photometry of additional variable stars in the same field of view. These results establish ASASSN-26ck as a new SU UMa-type dwarf nova. Further follow-up observations are encouraged to refine the superhump period and study its evolution. I will submit my observations to AAVSO, CBA and VSNET for further analysis. With kind regards, Tonny --- Tonny Vanmunster CBA Belgium Observatory CBA Extremadura Observatory http://www.cbabelgium.co <http://www.cbabelgium.com/> m

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