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

[vsnet-alert 28145] 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-alert 28143] 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-alert 28132] TCP J05384230+7051377: rebrightening
by Hiromasa Hoke 15 Jan '26

15 Jan '26

TCP J05384230+7051377: exhibit rebrightening Itoh-san, Kubotera-san, Tamas Tordai, Alexandra Zubareva, and David Messier have newly reported their observations. According to the data, this object showed a rebrightening, reaching a peak brightness of ~14 mag on 12/11. It was ~10 days to show the rebrightening. WZ Sge-type dwarf nova might exhibit multiple rebrightenings. This object possibly shows more rebrightening. Thus, further snapshots are very welcome. best regard, Hiromasa Hoke

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[vsnet-alert 28138] 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-alert 28135] 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-alert 28134] 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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[vsnet-alert 28130] ASASSN-25eq: new WZ Sge-type dwarf nova, likely a period bouncer
by Yusuke Tampo 17 Dec '25

17 Dec '25

ASASSN-25eq: new WZ Sge-type dwarf nova, likely a period bouncer ASASSN discovered ASASSN-25eq on 2025-11-13.18 UT at 15.07 mag. Then it brightened to g=14.0 mag on 2025-11-15. The VSX lists g=21.9 mag as the counterpart, hence the outburst amplitude is ~8 mag. https://vsx.aavso.org/index.php?view=detail.top&oid=10868208 https://asas-sn.osu.edu/sky-patrol/coordinate/579ca10e-176d-4c3b-958f-03a39… Josch Hambsh and Berto Monard have reported the time-resolved observations of ASASSN-25eq. The light curve shows a 1-mag dip around 2025-11-25 UT. After this dip, clear superhumps are present, with a period of ~0.0645 d. There is no clear modulation before the dip. Thus, ASASSN-25eq is a new WZ Sge-type dwarf nova, with a double-superoutburst feature often observed in a period bouncer system. See e.g. https://ui.adsabs.harvard.edu/abs/2018PASJ...70...47K/abstract Given the absence of clear early superhumps, ASASSN-25eq is presumably a face-on system. A spectrum taken with the Mookodi/Lesedi telescope on 16 Nov. is dominated by Balmer absorption lines, which supports this interpretation. Time-resolved 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-alert 28131] TCP J05384230+7051377: faded but might show rebrightenings
by Keisuke Isogai 02 Dec '25

02 Dec '25

TCP J05384230+7051377: faded but might show rebrightenings Itoh-san, David Messier, Franky Dubois, Tonny Vanmunster, Sano-san, and Kubotera-san reported their observations. This object showed clear superhumps with an averaged period of 0.06806(1) d. The 0.065 d period in the previous reports was an alias. The object rapidly faded from Nov 29, and now stays around 17.5 mag. The current state is even about 3 mag brighter than in quiescence, and this object might show some rebrightenings. Thus, further snapshots are very welcome.

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[vsnet-alert 28129] TCP J06364062+3318310: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 26 Nov '25

26 Nov '25

Dear colleagues, TCP J06364062+3318310 was discovered by K. Sokolovsky et al. (NMW Survey) on 2025 Nov 17.99 at mag 13.6CV. The quiescent counterpart is a 21.3 r mag star, implying an outburst amplitude of ~8 mag. I have just completed the analysis of my unfiltered CCD time-series observations of TCP J06364062+3318310, obtained on 2025 Nov 25/26 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 Nov 25/26, but those did not reveal any obvious modulation. In contrast, the Nov 25/26 light curve clearly shows regular superhump modulations with an amplitude of 0.30 mag. A period analysis using ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0661 +/- 0.0008d. The object was measured at mag CV = 15.3 on Nov 26th. 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 J06364062+3318310 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-alert 28120] TCP J05384230+7051377: new WZ Sge-type dwarf nova
by 保家大将 21 Nov '25

21 Nov '25

TCP J05384230+7051377: new WZ Sge-type dwarf nova We posted our spectroscopic follow-up result of TCP J05384230+7051377 to ATel. ATel #17485: Spectroscopic confirmation of TCP J05384230+7051377 as a WZ Sge-type dwarf nova <https://www.astronomerstelegram.org/?read=17485> We concluded that this object 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. Also, we estimated this object as p ~ 0.06d from Itoh-san's data. However p ~ 0.06d is a weak signal, so further observation will provide a more accurate estimate of the period. best regard, Hiromasa Hoke

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