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

[vsnet-alert 28111] TCP J03173646+7459318: a likely new WZ Sge-type dwarf nova
by tonny.vanmunster＠gmail.com 23 Sep '25

23 Sep '25

Dear colleagues, TCP J03173646+7459318 was discovered by XOSS (Xingming Observatory Sky Survey) on 2025 Sep 21.8 at mag 13.78C. The quiescent counterpart is a 20.9 V mag object, implying an outburst amplitude of ~8 mag. I have just completed the analysis of my unfiltered CCD observations of TCP J03173646+7459318, obtained on 2025 Sep 22/23 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. The light curve clearly reveals double-peaked modulations consistent with early superhumps, with an amplitude of 0.09 mag. A period analysis, using ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0600 +/- 0.0006d. The object was measured at mag CV = 13.6 on Sep 23rd. Image calibration and photometry were performed with the latest release of Phoranso, which enabled simultaneous photometry of several additional variable stars within the same frames. These findings strongly suggest that TCP J03173646+7459318 is a new WZ Sge-type dwarf nova. 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 28110] TCP J20143906+0352503: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 23 Sep '25

23 Sep '25

Dear colleagues, TCP J20143906+0352503 was discovered by XOSS (Xingming Observatory Sky Survey) on 2025 Sep 16.7 at mag 15.72C. The quiescent counterpart is possibly a 21.1 V mag star 2" to the W, implying an outburst amplitude of ~5 mag. I have just completed the analysis of my unfiltered CCD observations of TCP J20143906+0352503, obtained on 2025 Sep 22/23 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. The light curve clearly exhibits superhump modulations with an amplitude of 0.25 mag. Period analysis with ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0641 +/- 0.0006d. The object was measured at mag CV = 16.4 on Sep 23rd. Additional observations obtained on earlier nights (e.g. Sep 21/22) also showed superhump activity; however, the data sets were too short due to clouds to permit a reliable period determination. Image calibration and photometry were performed with the latest release of Phoranso, which enabled simultaneous photometry of several additional variable stars within the same frames. These results establish TCP J20143906+0352503 as a new SU UMa-type dwarf nova. Follow-up observations are encouraged. 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 28109] Var Pic 2008 outburst!
by Rod Stubbings 18 Sep '25

18 Sep '25

Var Pic 2008 is currently in an outburst. I commenced observing this field in 2015; however, I have not recorded any detections to date. To my knowledge, I am not aware of any reported outbursts since its discovery in 2008. VAR PIC 2008 250917.640 <154 VAR PIC 2008 250918.674 134 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 28108] ASASSN-25dt: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 12 Sep '25

12 Sep '25

Dear colleagues, ASASSN-25dt was discovered by the ASAS-SN Survey (Ohio State University) on 2025 Sep 05.3 at mag 14.5 V/g. The quiescent counterpart is a 20.1 g mag Pan-STARRS1 object, implying an outburst amplitude of ~5-6 mag. I have just completed the analysis of my unfiltered CCD observations of ASASSN-25dt, obtained on 2025 Sep 10/11 and Sep 11/12 at CBA Extremadura Observatory. The data were acquired under (mostly) clear skies with a 0.40-m f/5.1 telescope and a Moravian G2-4000 CCD. The Sep 10/11 light curve showed only irregular, small-amplitude variability. However, the Sep 11/12 light curve clearly exhibits superhump modulations with an amplitude of 0.27 mag. Period analysis with ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0605 +/- 0.0008d. The object was measured at mag CV = 15.9 on Sep 12th. Image calibration and photometry were carried out with the latest release of Phoranso. These results establish ASASSN-25dt as a new SU UMa-type dwarf nova. Follow-up observations are encouraged. 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 28107] TCP J21091443-0917104 (=ASASSN-25dq): new SU UMa-type dwarf nova
by Yusuke Tampo 08 Sep '25

08 Sep '25

TCP J21091443-0917104 (=ASASSN-25dq): new SU UMa-type dwarf nova NMW Survey discovered TCP J21091443-0917104 at 12.4 mag on 2025 08 22.8877 UCT. They suspected it could be a new UV Cet star based on its coincidence with the bright Gaia object (Gaia DR3 6896395696896704000; G=14.44, Plx=3.12 +/-0.04 mas). https://vsx.aavso.org/index.php?view=detail.top&oid=10867963 http://www.cbat.eps.harvard.edu/unconf/followups/J21091443-0917104.html S. Brincat and J. Hambsch have reported the time-resolved observations. Combining the observations by W. Goltz on AAVSO, I obtained a single-peak variation with a period of 0.05887(3) d, from the outburst maximum. ZTF light curve also shows a slow decline over the last two weeks, which is unlike a UV Cet star but agrees with a dwarf nova outburst. https://alerce.online/object/ZTF21abtlwbr Thus TCP J21091443-0917104 is most likely a new SU UMa-type dwarf nova. Considering its relatively short superhump period and expected large amplitude of outburst, the Gaia object can be a foreground star. The object is currently g=14.2 mag. 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 28106] TCP J17301230-2753488 (=AT 2025wyg): new classical nova
by Yusuke Tampo 07 Sep '25

07 Sep '25

TCP J17301230-2753488 (=AT 2025wyg): new classical nova We have posted the spectrum of TCP J17301230-2753488 to TNS taken with Lesedi/Mookodi at the Sutherland observatory of the South African Astronomical Observatory. The spectrum shows Balmer and Fe II P-Cygni profiles, hence classified as a classical nova. https://www.wis-tns.org/object/2025wyg 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 28102] T CrB: Possible onset of nova eruption
by Kojiguchi 05 Sep '25

05 Sep '25

T CrB: Possible onset of nova eruption According to a report posted to the VSOLJ mailing list by Iijima-san in Asiago, Italy, T CrB was measured at about 7 mag as of 21:00 UT on September 4, suggesting that a nova eruption might have begun. Further observations are strongly encouraged to confirm this report.

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[vsnet-alert 28101] Spectroscopic and photometric confirmation of TCP J22135399+3015357 as a WZ Sge-type dwarf nova
by Keisuke Isogai 22 Aug '25

22 Aug '25

Spectroscopic and photometric confirmation of TCP J22135399+3015357 as a WZ Sge-type dwarf nova We posted the results of our spectroscopic and photometric observations to ATel: https://www.astronomerstelegram.org/?read=17347 We confirmed that this object is a new WZ Sge-type dwarf nova with a large outburst amplitude.

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[vsnet-alert 28100] TCP J22135399+3015357: a likely new WZ Sge-type dwarf nova
by Tonny Vanmunster 21 Aug '25

21 Aug '25

Dear colleagues, TCP J22135399+3015357 was discovered by the NMW survey at the Astroverty astrofarm in Russia on 2025 Aug 19.8 at mag 13.6 CR. Archival images show that the object was already in outburst one day earlier. The quiescent counterpart is listed at 22.8 r mag, implying an outburst amplitude of ~9 mag. I have just completed the analysis of my unfiltered CCD observations of TCP J22135399+3015357, obtained on 2025 Aug 20/21 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. The light curve reveals clear double-peaked modulations consistent with early superhumps, with an amplitude of 0.11 mag. A period analysis, using ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0612 +/- 0.0012d. The object was measured at mag CV = 14.2 on Aug 20th. Image calibration and photometry were performed with the latest release of Phoranso. These findings strongly suggest that TCP J22135399+3015357 is a new WZ Sge-type dwarf nova. 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.com PERANSO : The Light Curve and Period Analysis Software http://www.peranso.com PHORANSO: Photometric Reduction and Analysis Software http://www.phoranso.com

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[vsnet-alert 28099] AT 2025tzw (TCP J21092606+3548416) - unclear type dwarf nova in superoutburst
by t9005780498＠gmail.com 17 Aug '25

17 Aug '25

Dear colleagues, The new dwarf nova AT 2025tzw (TCP J21092606+3548416) is now in superoutburst. Optical transient (15.6 in clear band) was detected at 2025-08-15 12:34:33.600 UT by Yuji Nakamura et al. ASAS-SN photometric survey detects AT 2025tzw at 2025-08-15.236 UT with g magnitude 15.866, and detects no transient 2025-08-14.245 UT with limit 16.594. ZTF shows quiescent state magnitude of about 21.5 and three missed historical superoutbursts in September 2023, April 2021 and June 2018, peaking at 16.2-16.4m in zg, which allows us to assume supercycle duration of about 3 years and superoutbursts amplitude of about 5.1-5.3m. The absence of normal outbursts makes the object's status ambiguous between the classical SU UMa and WZ Sge subgroups. Dr. N. P. Ikonnikova and Dr. S. Yu. Shugarov report presence of superhumps with period ~0.075 days and amplitude about 0.24m based on observations with 60cm Ritchey–Chrétien telescope at 2025-08-16. This may indicate the absence of the early superhumps phase. Color indices are U-B = -0.6 B-V = 0.12 V-R = 0.04 R-I = 0.1. R. Ottaviani and P. Ochner report spectroscopic classification of AT 2025tzw as CV star with a blue continuum with Balmer absorption except for H alpha. Classification report is available at https://www.wis-tns.org/object/2025tzw Monitoring photometric observations are encouraged. Sincerely, Alexander Tarasenkov

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