- vsnet-campaign-dn - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-campaign-dn 17586] AT2026ryu: new SU UMa-type dwarf nova, likely WZ Sge-type
by Yusuke Tampo 15 Jul '26

15 Jul '26

AT2026ryu: new SU UMa-type dwarf nova, likely WZ Sge-type Rui Min et al discovered AT2026ryu at 14.98 mag on 2026-07-06 15:01:24 UTC. The outburst amplitude is ~8 mag. ZTF also discovered this object as ZTF26abeziup. https://www.wis-tns.org/object/2026ryu https://vsx.aavso.org/index.php?view=detail.top&oid=10875920 Lesedi telescope at SAAO and Itoh-san have reported the time-resolved observations of AT2026ryu. The most recent observations on 14 July with Lesedi show ordinary superhumps with a period of ~0.0571 d. No clear modulations are present in the data on 6 and 7 July. Thus AT 2026ryu is a new SU UMa-type dwarf nova. Given its large outburst amplitude and long waiting time before the emergence of ordinary superhumps, AT 2026ryu is likely a WZ Sge-type dwarf nova. Time-resolved observations are encouraged to improve the period determination. 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-campaign-dn 17585] ASASSN-26ea: new SU UMa-type dwarf nova, likely WZ Sge-type
by Yusuke Tampo 15 Jul '26

15 Jul '26

ASASSN-26ea: new SU UMa-type dwarf nova ASASSN-26ea was discovered by ASASSN on 2026-07-5.07 at 16.67 mag. The time-resolved observations by Sjoerd Dufoer show ordinary superhumps with a period of ~0.058 d (other aliases possible). Thus ASASSN-26ea is a new SU UMa-type dwarf nova. Considering its large outburst amplitude (~8 mag according to the VSX) and short superhump period, ASASSN-26ea can be a WZ Sge-type dwarf nova. https://vsx.aavso.org/index.php?view=detail.top&oid=10875918 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-campaign-dn 17584] ASASSN-26dv: new SU UMa-type dwarf nova and a candidate period bouncer
by Yusuke Tampo 15 Jul '26

15 Jul '26

ASASSN-26dv: new SU UMa-type dwarf nova and a candidate period bouncer ASASSN-26dv was discovered by ASASSN on 2026-06-23.03 UT at 14.62 mag. After the initial decline, ATLAS and ASASSN light curves showed a short dip around 2026-07-05 UT. https://vsx.aavso.org/index.php?view=detail.top&oid=10875895 The time-resolved observations after this dip by Berto Monard show likely positive superhumps, with a period of ~0.055 d. Thus, ASASSN-26dv is a new SU UMa-type dwarf nova with a possible dip in the outburst plateau, which is often seen in outbursts in period bouncers. Further time-resolved observations are encouraged to establish its superhump period. 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-campaign-dn 17583] ASASSN-26dq (aka Gaia DR3 375654744699712512): new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 20 Jun '26

20 Jun '26

Dear colleagues, ASASSN-26dq (aka Gaia DR3 375654744699712512) was found in outburst by the ASAS-SN team on 2026 Jun 07.4 at mag g = 13.6. The quiescent counterpart is a 20.4 r mag star, implying an outburst amplitude of approximately 7 magnitudes. I obtained unfiltered CCD time-series photometry of ASASSN-26dq on 2026 Jun 13/14, Jun 15/16 and Jun 18/19, at CBA Extremadura Observatory using a 0.40-m f/5.1 telescope equipped with a Moravian G2-4000 CCD camera. Modulations were already apparent in the June 13/14 light curve, but the observing run was too short for a reliable period determination. Combining the three datasets in Peranso 3.1 allowed a robust period analysis using ANOVA, Lomb-Scargle, Generalized Lomb-Scargle and PDM methods. This revealed regular superhumps with an amplitude of 0.27 mag and a superhump period of 0.0567 +/- 0.0024 d. The object faded from mag 14.5 (unfiltered) on Jun 14th to mag 15.0 (unfiltered) on Jun 19th. 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 observations establish ASASSN-26dq as a new SU UMa-type dwarf nova. Continued time-series photometry is encouraged to refine the superhump period and monitor its evolution throughout the outburst. The observations will be submitted to AAVSO, CBA and VSNET for further analysis. With kind regards, Tonny Vanmunster CBA Belgium Observatory CBA Extremadura Observatory http://www.cbabelgium.co <http://www.cbabelgium.com/> m

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[vsnet-campaign-dn 17582] TCP J00560713+4301406: new large-amplitude outburst, likely a dwarf nova
by Yusuke Tampo 01 Jun '26

01 Jun '26

TCP J00560713+4301406: new large-amplitude outburst, likely a dwarf nova TCP J00560713+4301406 was discovered at 12.2 mag on 2026 06 01.4 UTC. http://www.cbat.eps.harvard.edu/unconf/followups/J00560713+4301406.html ATLAS also detected this outburst on 2026 05 31.6 UTC around 15.5 mag, likely on the rise. There is a possible counterpart at ~3" away; Gaia 375654744699712512 at ~20.36 mag, thus, the outburst amplitude is ~8 mag. Its blue color (BP-RP~0.34 mag) and distance 1049(-400/+1016) pc are consistent with a counterpart being a CV with a low mass-transfer rate. Although the visibility is not great, time-resolved photometry or snap spectroscopy to confirm its nature is encouraged. 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-campaign-dn 17579] ATLAS26dqo: new WZ Sge-type dwarf nova
by tonny.vanmunster＠gmail.com 19 Apr '26

19 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-campaign-dn 17578] 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-campaign-dn 17577] 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-campaign-dn 17576] 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-campaign-dn 17575] 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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