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

[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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[vsnet-alert 28154] TCP J08460573+1047397: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 03 Apr '26

03 Apr '26

Dear colleagues, TCP J08460573+1047397 was discovered by the NMW-TexasTech transient survey (K. Sokolovsky et. al.) on 2026 Mar 21.2 at mag CV = 14.5. The quiescent counterpart is a 22.5 g mag star, implying an outburst amplitude of ~8 mag. I have just completed the analysis of my unfiltered CCD time-series observations of TCP J08460573+1047397, obtained on 2026 Mar 31/Apr 01 at CBA Belgium Observatory. The data were acquired under mostly clear skies with a 0.40-m f/10.0 telescope and a QHY-268M CMOS camera. I have observed this object on several nights between Mar 21st and Apr 01st but no obvious modulations were seen. However, the Mar 31/Apr 01 light curve clearly shows regular superhump modulations with an amplitude of 0.18 mag. A period analysis using ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0643 +/- 0.0008d. The object was measured at mag CV = 15.6 on Apr 01st. 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 TCP J08460573+1047397 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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[vsnet-alert 28153] TCP J07264579-2745141 : new SU UMa-type dwarf nova, and possibly WZ Sge-type one
by Hiromasa Hoke 27 Mar '26

27 Mar '26

dear all, TCP J07264579-2745141 : new SU UMa-type dwarf nova, and possibly WZ Sge-type one Itagaki-san discovered TCP J07264579-2745141 on 2026-03-17.4417 UTC at 14.8 mag (unfiltered). According to VSX, this object's quiescence magnitude is g~21.6 thus, the outburst amplitude is ~7 mag. https://vsx.aavso.org/index.php?view=detail.top&oid=10872106 Josch Hambsch and Moriyama-san reported the time-resolved observations. These light curves (after 2026-3-19 UTC) show ordinary superhumps with an amplitude of ~0.2 mag and a period of 0.05475(3)d. Hence, TCP J07264579-2745141 is a new SU UMa-type dwarf nova. Due to the sparse coverage before March 19, we cannot judge if TCP J07264579-2745141 showed early superhumps. Given the large outburst amplitude and short superhump period, it can be a WZ Sge-type dwarf nova. Best regards, Hiromasa

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[vsnet-alert 28152] ASASSN-26bv: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 24 Mar '26

24 Mar '26

Dear colleagues, ASASSN-26bv was discovered by the ASAS-SN team on 2026 Mar 15.1 at mag g = 17.1. I have just completed the analysis of my unfiltered CCD time-series observations of ASASSN-26bv, obtained on 2026 Mar 22/23 and Mar 23/24 at CBA Extremadura Observatory. The data were acquired under clear skies with a 0.40-m f/5.1 telescope and a Moravian G2-4000 CCD camera. The combined light curve clearly shows regular superhump modulations with an amplitude of 0.45 mag. A period analysis using ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0565 +/- 0.0003d. The object was measured at mag CV = 16.6 on Mar 24th. 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-26bv 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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[vsnet-alert 28151] TCP J07032576-1241401: updated superhump period
by Yusuke Tampo 16 Mar '26

16 Mar '26

TCP J07032576-1241401: updated superhump period Along with Peter Starr, Josch Hambsh and Itoh-san have reported the time-resolved observations of TCP J07032576-1241401. Using these data, the updated superhump period is 0.06661(1) d, roughly consistent with Peter Starr's previous estimate. ATLAS has detected multiple superoutbursts over the years, with an approximate superoutburst cycle of ~300 days. https://fallingstar-data.com/forcedphot/queue/3994466/ Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow Yusuke TAMPO / 反保雄介 EMAIL: tampo(a)kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-alert 28148] TCP J08011102-0343141; new WZ Sge-type dwarf nova
by Yusuke Tampo 11 Mar '26

11 Mar '26

TCP J08011102-0343141; new WZ Sge-type dwarf nova TCP J08011102-0343141 was discovered by the XOSS team on 2026 02 08.8 UT at 15.1 mag. http://www.cbat.eps.harvard.edu/unconf/followups/J08011102-0343141.html Itoh-san has reported the time-resolved observations of TCP J08011102-0343141. The light curve shows double-peaked modulation with a period of ~0.069 d and an amplitude of ~0.02 mag, although 1-d-aliased periods are still possible. Given its large outburst amplitude of ~8 mag, this is most likely early superhumps of a WZ Sge-type dwarf nova. I also obtained an optical spectrum of TCP J08011102-0343141 with the 1.9m telescope at the SAAO Sutherland Observatory on 2026 02 09 UT. The spectrum shows Balmer absorption lines, consistent with this classification. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow Yusuke TAMPO / 反保雄介 EMAIL: tampo(a)kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke(a)saao.ac.za ----------------------------------------------

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