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

[vsnet-outburst 31534] ASASSN-25dc; a new candidate of a WZ Sge-type dwarf nova with the double superoutburst
by Yusuke Tampo 13 Aug '25

13 Aug '25

ASASSN-25dc; a new candidate of a WZ Sge-type dwarf nova with the double superoutburst ASASSN-25dc was discovered by ASAS-SN on 2025-07-13.09 UTC at g=13.07. This outburst is also observed by ATLAS, o~15.2 mag on 2025-07-07.8 UTC and o~13.5 mag on 2025-07-10.9 UTC. The likely counterpart is Gaia DR3 6129070308813533568 with G~21.0 mag, hence the outburst amplitude is ~7.0 mag. This system underwent a short dip on 16-17th July, around 14.5 mag, and is now recovering from the dip. Lesedi telescope at Sutherland, Josch Hambsh, and Berto Monard have reported the time-resolved observations of ASASSN-25dc. PDM analysis using the overall data yields a single-peaked modulation with a period of 0.05991(4) d and an amplitude of 0.03 mag. Combining the 1-mag dip feature on the light curve and short superhump period, ASASSN-25dc can be a similar system to double-superoutburst WZ Sge-type dwarf novae, especially the period-bouncer candidates ASASSN-15jd and ASASSN-16hg (see Kimura et al. 2016,2018). https://arxiv.org/abs/1604.06344 https://arxiv.org/abs/1803.03179 The ongoing second outburst should show the evolution of ordinary superhumps. The hint of ordinary superhumps is seen in the observations on 17th July. 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-outburst 31547] Outbursts 11/08/2025
by Rod Stubbings 12 Aug '25

12 Aug '25

Outbursts detected on 11/08/2025 object YYMMDD(UT) mag code remarks ARAAT 250811.502 140 Stu.RASNZ outburst INDTU 250811.404 153 Stu.RASNZ outburst ASASSN-14IK 250811.407 143 Stu.RASNZ outburst LMC V3434 250811.384 144 Stu.RASNZ outburst -- 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-outburst 31546] Outbursts 10/08/2025
by Rod Stubbings 10 Aug '25

10 Aug '25

Detected outbursts tonight. object YYMMDD(UT) mag code remarks AQLUU 250810.506 120 Stu.RASNZ outburst ARAV793 250810.519 149 Stu.RASNZ outburst CENV436 250810.387 123 Stu.RASNZ outburst CENV442 250810.386 126 Stu.RASNZ outburst CRABP 250810.377 144 Stu.RASNZ outburst DELHO 250810.501 137 Stu.RASNZ outburst SCOV598 250810.373 148 Stu.RASNZ outburst SERUZ 250810.384 134 Stu.RASNZ outburst SGRV729 250810.372 141 Stu.RASNZ outburst SGRV1830 250810.382 126 Stu.RASNZ outburst TRADV 250810.517 130 Stu.RASNZ outburst ASASSN-14FE 250810.601 138 Stu.RASNZ outburst ASASSN-19CT 250810.388 142 Stu.RASNZ outburst -- 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-outburst 31545] ASASSN-25df; new SU UMa-type dwarf nova
by Yusuke Tampo 08 Aug '25

08 Aug '25

ASASSN-25df; new SU UMa-type dwarf nova ASASSN-25df was discovered by ASAS-SN on 2025-07-28.02 UTC at g=13.51 mag. The outburst amplitude is ~8.0 mag. ATLAS has also detected this outburst since 2025-07-25. https://vsx.aavso.org/index.php?view=detail.top&oid=10867883 Josch Hambsh reported the time-resolved observations. The observations after 2025-08-02 show strong variations with an amplitude of ~0.1 mag. Due to the short baselines because of its RA~12.5 hr, the superhump period is not well constrained; a possible period is ~0.067 d, but other aliases are equally possible. Thus, I conclude that ASASSN-25df is a new SU UMa-type dwarf nova. A waiting time of ~7 days before the appearance of ordinary superhumps suggests that ASASSN-25df can be a WZ Sge-type dwarf nova. 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-outburst 31539] TCP J16271026-1030020: a new WZ Sge-type dwarf nova candidate possibly with large-amplitude early superhump
by Yusuke Tampo 05 Aug '25

05 Aug '25

TCP J16271026-1030020: a new WZ Sge-type dwarf nova candidate possibly with large-amplitude early superhump TCP J16271026-1030020 was discovered by T. Kojima on 2025-07-25.52 UTC at 13.8 mag (unfiltered). ATLAS force photometry and ASASSN also detect this outburst since 2025-07-22.3 UTC, peaking around g~12.6 mag. The Pan-STARRS1 counterpart is g=22.1(2) mag, giving the outburst amplitude of ~9.5 mag. http://www.cbat.eps.harvard.edu/unconf/followups/J16271026-1030020.html https://vsx.aavso.org/index.php?view=detail.top&oid=10867693 I have obtained the low-resolution spectrum with the Lesedi telescope at the SAAO Sutherland. This spectrum shows prominent Balmer, He II 4686, and other He I emission lines with no absorption features. Itoh-san also reported the time-resolved observations for ~45 min. The light curve shows a modulation of ~0.2 mag. These overall features suggest that TCP J16271026-1030020 is a new large-amplitude dwarf nova, most likely a WZ Sge-type, showing relatively large early superhump amplitude. Further time-resolved observations (with multiple bands, if possible) and time-resolved spectroscopy 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-outburst 31543] Outbursts 2/08/2025
by Rod Stubbings 03 Aug '25

03 Aug '25

Outbursts detected 2/08/2025 object YYMMDD(UT) mag code remarks HYIWX 250802.575 140 Stu.RASNZ outburst PAVGS 250802.432 154 Stu.RASNZ outburst PEGHX 250802.386 146 Stu.RASNZ outburst NSV 35 250802.577 150 Stu.RASNZ outburst -- 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-outburst 31541] Recent outbursts
by Rod Stubbings 31 Jul '25

31 Jul '25

Outbursts detected the pas two nights. object YYMMDD(UT) mag code remarks CENMU 250730.415 132 Stu.RASNZ outburst HYAV392 250731.379 148 Stu.RASNZ outburst HYIWX 250730.531 138 Stu.RASNZ outburst HYIDR 250730.531 151 Stu.RASNZ outburst LUPBR 250730.535 145 Stu.RASNZ outburst NORHP 250731.617 145 Stu.RASNZ outburst PEGHX 250731.655 132 Stu.RASNZ outburst TELKK 250730.435 139 Stu.RASNZ outburst ASASSN-14CF 250731.442 151 Stu.RASNZ outburst ASASSN-14LK 250730.425 144 Stu.RASNZ outburst DDE 77 250731.647 136 Stu.RASNZ outburst -- 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-outburst 31540] Outbursts 29/07/2025
by Rod Stubbings 29 Jul '25

29 Jul '25

Outbursts detected, 29/07/2025 object YYMMDD(UT) mag code remarks CENNN 250729.381 154 Stu.RASNZ outburst CENV359 250729.387 147 Stu.RASNZ outburst INDTU 250729.400 142 Stu.RASNZ outburst MUSDQ 250729.380 150 Stu.RASNZ outburst OCTAA 250729.419 148 Stu.RASNZ outburst OPHV699 250729.395 150 Stu.RASNZ outburst SCOFQ 250729.364 135 Stu.RASNZ outburst VIRHS 250729.376 146 Stu.RASNZ outburst NSV 11274 250729.382 152 Stu.RASNZ outburst MASTER OT J142023.47-485540.0 250729.440 134 Stu.RASNZ outburst CTCVJ1940-4724 250729.383 144 Stu.RASNZ outburst -- 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-outburst 31537] TCP J19181542+3158142: likely a new WZ Sge-type dwarf nova
by Yusuke Tampo 23 Jul '25

23 Jul '25

TCP J19181542+3158142: likely a new WZ Sge-type dwarf nova TCP J19181542+3158142 was discovered by the XOSS team on 18 July at 15.22 mag. The quiescence counterpart is a Pan-STARRS1 source with r=21.35(3) mag, indicating the outburst amplitude of ~6 mag. Itoh-san reported the time-resolved observations for three nights on 19-21 July. Although the scatter is large, PDM analysis yields a period of 0.05525(7) d, with an amplitude of ~0.1 mag and a double-peaked profile, probably early superhumps. Thus, TCP J19181542+3158142 is likely a new WZ Sge-type dwarf nova. This system is a bit faint for time-resolved observations (currently ~15.8 mag), but further observations are encouraged to confirm its superhump profile and evolution. 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-outburst 31536] Outbursts 22/07/2025
by Rod Stubbings 22 Jul '25

22 Jul '25

Outbursts observed 22/07/2025 object YYMMDD(UT) mag code remarks AQRQU 250722.556 160 Stu.RASNZ outburst ARABF 250722.419 142 Stu.RASNZ outburst CAROQ 250722.374 141 Stu.RASNZ outburst CENV342 250722.371 143 Stu.RASNZ outburst CRABP 250722.380 140 Stu.RASNZ outburst CRTBF 250722.368 144 Stu.RASNZ outburst LUPBR 250722.565 145 Stu.RASNZ outburst PAVAS 250722.428 150 Stu.RASNZ outburst PAVGS 250722.385 148 Stu.RASNZ outburst SGRV730 250722.381 151 Stu.RASNZ outburst VIRTW 250722.369 131 Stu.RASNZ outburst VIRHS 250722.431 148 Stu.RASNZ outburst ASASSN-19CT 250722.367 138 Stu.RASNZ outburst -- 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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