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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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[vsnet-campaign-dn 17573] TCP J08011102-0343141; new WZ Sge-type dwarf nova
by Yusuke Tampo 23 Feb '26

23 Feb '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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[vsnet-campaign-dn 17563] Outburst from a WZ Sge-type dwarf nova HV Vir
by Yusuke Tampo 29 Jan '26

29 Jan '26

Outburst from a WZ Sge-type dwarf nova HV Vir Gary Poyner reported a new outburst from a known WZ Sge-type dwarf nova HV Vir, at V=11.964 mag on 2026/01/05 06:59:02 UTC. https://www.aavso.org/LCGv2/static.htm?DateFormat=Julian&RequestedBands=&Gr… Vir&tojd=2461046.180&delimiter=@@@ Time-resolved observations are encouraged. Best regards & Happy new year! 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 17571] TCPJ06571119-1724439: most likely a new WZ Sge-type dwarf nova
by Yusuke Tampo 20 Jan '26

20 Jan '26

TCPJ06571119-1724439: most likely a new WZ Sge-type dwarf nova Yuji Nakamura discovered TCPJ06571119-1724439 on 2026 01 18.5375 UTC at 14.2 mag. http://www.cbat.eps.harvard.edu/unconf/followups/J06571119-1724439.html I have observed TCPJ06571119-1724439 with the Lesedi telescope at the Sutherland observatory on 18 and 19 Jan. The light curve shows double-peaked modulations with a period of ~0.0550 d and an amplitude of ~0.08 mag. Thus TCPJ06571119-1724439 is most likely a new WZ Sge-type dwarf nova. Further observations are 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 17570] TCP J07353147+0910341: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 16 Jan '26

16 Jan '26

Dear colleagues, TCP J07353147+0910341 was discovered by XOSS (Xingming Observatory Sky Survey) on 2025 Dec 29.75 at mag 14.8 C. The quiescent counterpart is a 22.4 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 J07353147+0910341, obtained on 2026 Jan 14/15 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. I also obtained observations on several nights prior to Jan 14/15, but those did not reveal any obvious modulation. In contrast, the Jan 14/15 light curve clearly shows regular superhump modulations with an amplitude of 0.25 mag. A period analysis using ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0660 +/- 0.0008d. The object was measured at mag CV = 16.1 on Jan 14th. Image calibration and photometry were carried out using the latest release of Phoranso, which enabled simultaneous photometry of several additional variable stars in the same field of view. These results establish TCP J07353147+0910341 as a new SU UMa-type dwarf nova. Further follow-up observations are strongly 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 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 17568] ASASSN-26ad; new SU UMa-type dwarf nova, likely a WZ Sge star
by Yusuke Tampo 15 Jan '26

15 Jan '26

ASASSN-26ad; new SU UMa-type dwarf nova, likely a WZ Sge star ASASSN-26ad was discovered by ASASSN on 2026-01-04.1 UT at 14.57 mag. The outburst amplitude is ~8.3 mag according to the VSX. https://vsx.aavso.org/index.php?view=detail.top&oid=10868368 Sjoerd Dufoer, Josch Hambsch, and Itoh-san have reported the time-resolved observations. Although there were some modulations from the early outburst, clear single-peaked superhumps have appeared after 2026-01-10. The mean superhump period is ~0.0618 d. Thus, ASASSN-26ad is a new SU UMa-type dwarf nova. Given its large outburst amplitude and long waiting time before the appearance of positive superhumps, ASASSN-26ad is likely a WZ Sge star. 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 17564] ASASSN-25fj; new SU UMa-type dwarf nova, most likely WZ Sge subtype
by Yusuke Tampo 11 Jan '26

11 Jan '26

ASASSN-25fj; new SU UMa-type dwarf nova, most likely WZ Sge type ASASSN reported the discovery of ASASSN-25fj on 2026-01-1.19 UT. The observed maximum was approximately at 12.2 mag on 2025-12-25.0 UT according to ASASSN. https://asas-sn.osu.edu/sky-patrol/coordinate/ec92b0f6-1377-450b-b464-7fbe3… The likely counterpart is GALEX J050001.2-571430 (NUV=21.5(2) mag) and DES J050001.26-571430.1 (g=21.278(9) mag). Thus the outburst amplitude is ~9mag. Lesedi telescope at the SAAO and Josch Hambsch have reported the time-resolved observations of ASASSN-25fj. Its light curve after 2026-01-03 shows single-peaked ordinary superhumps with a period of ~0.0556 d and an amplitude of > 0.1 mag. Hence, ASASSN-25fj is a new SU UMa-type dwarf nova. Given its large outburst amplitude and short superhump period, it most likely belongs to the WZ Sge subtype. Continuous observations are 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 17562] TCP J16425922+2621020: a large amplitude CV candidate, likely a WZ Sge-type dwarf nova
by Yusuke Tampo 27 Dec '25

27 Dec '25

TCP J16425922+2621020: a large amplitude CV candidate, likely a WZ Sge-type dwarf nova Tadashi Kojima reported the discovery of TCP J16425922+2621020 on 2025 12 26.8538 UTC at 13.0 mag (unfiltered). http://www.cbat.eps.harvard.edu/unconf/followups/J16425922+2621020.html The likely counterpart is 3"-away Gaia DR3 1301247792154799488, G=20.044(8) mag at 674 (-144/+248) pc. Thus, the absolute magnitudes in quiescence and outburst are ~10.9(7) and ~3.9(7) mag, respectively. This is also recorded in the Gaia white dwarf candidate catalogs (e.g., Gentile et al. 2021). http://vizier.cds.unistra.fr/viz-bin/VizieR?-source=&-out.add=_r&-out.add=_… Given its large outburst amplitude of ~7 mag, no previous outbursts, and possible white dwarf-dominated spectral energy distribution in quiescence, TCP J16425922+2621020 is most likely a WZ Sge-type dwarf nova in outburst. Although time-resolved observations are almost impossible for now due to its RA=16hr, this might be a nice target for future observations. 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 17561] ASASSN-22nd (=AT2025ahnc= ZTF25acibbkf =ASASSN-25fb); a new fast-decaying outburst
by Yusuke Tampo 19 Dec '25

19 Dec '25

ASASSN-22nd (=AT2025ahnc= ZTF25acibbkf =ASASSN-25fb); a new fast-decaying outburst GOTO, ZTF, and ASASSN have detected a new outburst from a known CV candidate ASASSN-22nd. https://vsx.aavso.org/index.php?view=detail.top&oid=2345330 https://www.wis-tns.org/object/2025ahnc https://lasair-ztf.lsst.ac.uk/objects/ZTF25acibbkf/ https://asas-sn.osu.edu/sky-patrol/coordinate/19517db9-fb36-4d9c-a94d-2ca87… This outburst shows a fast decay, approximately 1 mag/d. Considering its large amplitude(>7mag), relatively short outburst cycle (~3 years), and fast decay of the outburst, this outburst could be a precursor outburst of a dwarf nova superoutburst, or even from an AM CVn star. Although the system is currently faint (~18.5 mag in ATLAS), if the system returns to a bright state, time-resolved photometries will be 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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