June 2025 - vsnet-campaign-dn - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-campaign-dn 17533] ASASSN-25cu: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 29 Jun '25

29 Jun '25

Dear colleagues, I have just completed the analysis of my unfiltered CCD observations of ASASSN-25cu, obtained on Jun 27/28 and 28/29, 2025 at CBA Belgium Observatory. The data was collected using a 0.40-m f/10.0 telescope and QHY-268M CMOS camera under clear skies. The light curve clearly reveals the presence of regular superhumps with an amplitude of 0.25 mag, establishing ASASSN-25cu as a new SU UMa-type dwarf nova. A period analysis, using the ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0536 +/- 0.0014d. The object was measured at mag CV = 15.7 on Jun 29th. Image calibration and photometry were performed using the latest release of Phoranso. Further observations are encouraged to refine the superhump period. 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 17532] asassn-25ca, -25ce, -25ch at KKO
by Berto Monard 05 Jun '25

05 Jun '25

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[vsnet-campaign-dn 17531] TCP J20131357+1154031: new SU UMa-type dwarf nova, possibly WZ Sge-type
by Yusuke Tampo 03 Jun '25

03 Jun '25

TCP J20131357+1154031: new SU UMa-type dwarf nova, possibly WZ Sge-type K. Itagaki discovered TCP J20131357+1154031 on 2025-05-19 UTC at 14.7 mag (unfiltered). The outburst amplitude is ~8.4 mag. https://www.aavso.org/vsx/index.php?view=detail.top&oid=10848625 SAAO/Lesedi telescope, Josch Hambsch, and Sano-san have reported the time-resolved observations. Josch's observations after 28 May show single-peaked variation with a period of 0.05797(6) d, likely an ordinary superhump. No clear modulations were presented before this. Thus TCP J20131357+1154031 is a new SU UMa-type dwarf nova and a good candidate for a WZ Sge-type dwarf nova, given its late appearance of ordinary superhumps. 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 17530] ASASSN-25ce: new WZ Sge-type dwarf nova
by Yusuke Tampo 02 Jun '25

02 Jun '25

ASASSN-25ce: new WZ Sge-type dwarf nova ASAS-SN discovered ASASSN-25ce on 2025-05-28 UTC at 12.26 mag. The Gaia counterpart is G~20.7 mag thus the outburst amplitude is ~8.5 mag. The SAAO team and Berto Monard reported the time-resolved observations. These light curves show a double-peak modulation with an amplitude of ~0.1 mag and a period of ~0.05537(1) d. The 5-sec resolution observations by the SAAO/Lesedi telescope also show QPO-like modulation with 5--10 min. Hence, ASASSN-25ce is a new WZ Sge-type dwarf nova, possibly with a relatively higher inclination, while no clear eclipses are present. Further 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-campaign-dn 17529] asassn-25ca, -25ce on 31 May at KKO
by Berto Monard 01 Jun '25

01 Jun '25

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