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

[vsnet-alert 28047] ASASSN-25ao
by Berto Monard 05 Feb '25

05 Feb '25

Hello, ASASSN-25ao, an outbursting blue object was observed at CBA-KKO on 3 and 4 Feb 2026. The object faded from an average of 15.85 to 16.16 CR (unfiltered magnitudes) over that period. The light curves showed a modulation hinting at a main period around 0.12d and a strong secondary period of 0.030d +/- 0.0005d, derived from GLS and PDM methods in Peranso. Further observations are planned for Friday 7 Feb, when skies will be clear again. Berto Monard / CBA KKO Calitzdorp, South Africa

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[vsnet-alert 28046] V4141Sgr outburst
by Tadashi Kojima 03 Feb '25

03 Feb '25

object YYYYMMDD(UT) mag V4141Sgr 20250203.8359 13.7c Observer: Tadashi Kojima (Tsumagoi,Gunma, Japan) Instruments:fl=300mm lens +Canon EOS6D digital camera

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[vsnet-alert 28041] TCP J04272195-2528038; possibly a new AM CVn star in outburst?
by Yusuke Tampo 02 Feb '25

02 Feb '25

TCP J04272195-2528038; possibly a new AM CVn star in outburst? TCP J04272195-2528038 was discovered by Y. Nakamura on 2025-01-09.4837 UT at 14.2 mag. The quiescence counterpart is g_PS1=21.09(5) mag, thus outburst amplitude is ~7 mag. http://www.cbat.eps.harvard.edu/unconf/followups/J04272195-2528038.html https://www.aavso.org/vsx/index.php?view=detail.top&oid=2391199 Itoh-san and myself using the SAAO/Lesedi telescope have reported the time-resolved observations. The SAAO data shows a possible double-peaked modulation with a period of ~42.6 min. In addition, the optical spectrum I obtained with the 1.9m telescope at the SAAO shows only the He I absorption lines, lacking any significant Balmer emission/absorption lines. Further observations are encouraged to establish its classification and determine the variation period. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow 反保雄介 Yusuke TAMPO MAIL: tampo(a)kusastro.kyoto-u.ac.jp MAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-alert 28040] TCP J17374270+4915116: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 30 Dec '24

30 Dec '24

Dear colleagues, I have just finished analysing my unfiltered CCD observations of TCP J17374270+4915116, obtained over the past 7 nights between 2024, Dec 23/24 and 29/30 at CBA Extremadura Observatory (Spain) using a 0.40-m f/5.1 telescope and SX-46 CCD camera under clear skies. The object started to develop superhumps on Dec 28/29, which further developed on Dec 29/30. The resulting light curve clearly shows the presence of regular superhumps with an amplitude of 0.25 mag, establishing TCP J17374270+4915116 as a new SU UMa-type dwarf nova. A period analysis, using the ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.0) yields a combined superhump period of 0.0589 +/- 0.0002d. The object was at mag CV = 14.6 on Dec 30th. Image calibration and photometry were done using Phoranso, which allowed me to simultaenously measure other variables present in the FOV of this new SU UMa-type dwarf nova. I will send 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 *** NEW *** http://www.phoranso.com <http://www.phoranso.com/>

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[vsnet-alert 28039] ASASSN-24hd is a ugwz star in outburst
by Berto Monard 27 Dec '24

27 Dec '24

Hello, Timeseries observations of ASASSN-24hd through a V filter were done on 24 and 25 Dec 2024 at CBA KKO. They covered the epochs JD 2460669.35-2460669.48 and JD 2460670.34-2460670.51 respectively. The LCs on both nights showed a clear periodic modulation (superhumps) in the shape of a saw tooth, a pattern that seems to occur with many outbursting ugwz stars seen over the years. The amplitude of the cyclic modulation during those nights were about .25V and .20V resp. and the mean brightness's were 12.79V and 12.92V. A period analysis using the PDM and GLS methods with Peranso 3.0 yielded a period of 0.583d +/- 0.003d on both nights, and considering the total observing baseline over the two nights a mean period of 0.580d +/- .0015d was derived. Earlier observations done on 19 Dec (mid-time JD 2460664.38) showed the object at a brightness of 12.06V but without any clear modulation. From the discovery data it can be concluded that the superhumps started between 8 and 12 days into the outburst. The large amplitude outburst, the considerable delay in the formation of superhumps, the LC pattern of the superhumps and the relative short periodicity of them ought to direct towards the ugwz status of ASASSN-24hd. Further observations are planned, weather allowing Berto Monard / CBA KKO Calitzdorp / South Africa

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[vsnet-alert 28038] TCP J03493487+3607319 (aka ASASSN-24hf): new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 26 Dec '24

26 Dec '24

Dear colleagues, I have just finished analysing my unfiltered CCD observations of TCP J03493487+3607319 (aka ASASSN-24hf), obtained on 2024, Dec 23/24, 24/25 and 25/26 at CBA Extremadura Observatory (Spain) using a 0.40-m f/5.1 telescope and SX-46 CCD camera under clear skies. The resulting light curve clearly shows the presence of regular superhumps with an amplitude of 0.23 mag, establishing TCP J03493487+3607319 as a new SU UMa-type dwarf nova. A period analysis, using the ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.0) yields a combined superhump period of 0.0697 +/- 0.0002d. The object was at mag CV = 16.7 on Dec 26th. Image calibration and photometry were done using Phoranso, which allowed me to simultaenously measure other variables present in the FOV of this new SU UMa-type dwarf nova. I will send 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 *** NEW *** http://www.phoranso.com <http://www.phoranso.com/>

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[vsnet-alert 28037] TCP J23291172+4127354: new eclipsing WZ Sge-type dwarf nova
by Yusuke Tampo 07 Dec '24

07 Dec '24

TCP J23291172+4127354: new eclipsing WZ Sge-type dwarf nova TCP J23291172+4127354 was discovered by Y. Nakamura on 2024-12-04.5385 at 14.1 mag (unfiltered). The counterpart in Pan-STARRS1 is g= 21.6 mag (objID= 157753522991272187), hence the outburst amplitude is ~7.5 mag. http://www.cbat.eps.harvard.edu/unconf/followups/J23291172+4127354.html https://www.aavso.org/vsx/index.php?view=detail.top&oid=2390566 Time-resolved observations reported by Itoh-san on the 5th and 6th Dec show double-peaked profiles and superposed eclipses. Its period and amplitude are obtained as 0.05693(2) d and ~0.5 mag (0.3 mag hump + 0.3 mag eclipse). Thus TCP J23291172+4127354 is a new (and yet another!) eclipsing WZ Sge-type dwarf nova. This would be another nice target for time-resolved photometries. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow 反保雄介　Yusuke TAMPO MAIL: tampo(a)kusastro.kyoto-u.ac.jp MAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-alert 28034] Gaia DR3 3130088774241620608: confirmation as a WZ Sge-type dwarf nova
by Yusuke Tampo 04 Dec '24

04 Dec '24

Gaia DR3 3130088774241620608: confirmation as a WZ Sge-type dwarf nova Itoh-san and J. Hambsch have reported the time-resolved observations of Gaia DR3 3130088774241620608 = TCP J06330104+0303350. The light curve shows a large-amplitude double-hump profile and superposed eclipses. Combining with AAVSO observations by J. Zhao, I obtained the early superhump+eclipse period as 0.05786(1) d. The orbital profile amplitude is ~0.5 mag; 0.3 mag early superhump plus 0.3 mag eclipse. Therefore, Gaia DR3 3130088774241620608 is now confirmed as an eclipsing WZ Sge-type. Time-resolved observations are strongly encouraged! best regards, Yusuke 2024年11月29日(金) 15:56 Yusuke Tampo <tampo(a)kusastro.kyoto-u.ac.jp>: > > TCP J06330104+0303350 = Gaia DR3 3130088774241620608 > > TCP J06330104+0303350 was discovered by T. Kojima on 2024-11-28.76 at > 13.9 mag and now brightened to V=13.4 mag according to TOCP reports. > http://www.cbat.eps.harvard.edu/unconf/followups/J06330104+0303350.html > > This system has already been pointed as a WZ Sge-type cataclysmic > variable candidate in Inight et al 2024, named Gaia DR3 > 3130088774241620608. > https://www.aavso.org/vsx/index.php?view=detail.top&oid=2389763 > https://ui.adsabs.harvard.edu/abs/2024MNRAS.tmp.2451I/abstract > > This outburst is a great opportunity to determine its outburst nature > as well as derive its superhump periods. > Time-resolved observations are encouraged. > > Best regards > Yusuke > > -- > ---------------------------------------------- > > South African Astronomical Observatory, Postdoc fellow > 反保雄介　Yusuke TAMPO > MAIL: tampo(a)kusastro.kyoto-u.ac.jp > MAIL: yusuke(a)saao.ac.za > > ---------------------------------------------- -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow 反保雄介　Yusuke TAMPO MAIL: tampo(a)kusastro.kyoto-u.ac.jp MAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-alert 28035] TCP J01330474+3913194: new eclipsing WZ Sge star
by Kojiguchi 03 Dec '24

03 Dec '24

TCP J01330474+3913194: new eclipsing WZ Sge Star Itoh-san has reported time-resolved observations. Moriyama-san has also reported snapshots. The light curve shows an overlapping profile of early superhumps and eclipses. The period and amplitude are 0.0551(1) d and about 0.8 mag, respectively. Further observations are encouraged.

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[vsnet-alert 28033] TCP J06330104+0303350 = Gaia DR3 3130088774241620608
by Yusuke Tampo 29 Nov '24

29 Nov '24

TCP J06330104+0303350 = Gaia DR3 3130088774241620608 TCP J06330104+0303350 was discovered by T. Kojima on 2024-11-28.76 at 13.9 mag and now brightened to V=13.4 mag according to TOCP reports. http://www.cbat.eps.harvard.edu/unconf/followups/J06330104+0303350.html This system has already been pointed as a WZ Sge-type cataclysmic variable candidate in Inight et al 2024, named Gaia DR3 3130088774241620608. https://www.aavso.org/vsx/index.php?view=detail.top&oid=2389763 https://ui.adsabs.harvard.edu/abs/2024MNRAS.tmp.2451I/abstract This outburst is a great opportunity to determine its outburst nature as well as derive its superhump periods. Time-resolved observations are encouraged. Best regards Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow 反保雄介　Yusuke TAMPO MAIL: tampo(a)kusastro.kyoto-u.ac.jp MAIL: yusuke(a)saao.ac.za ----------------------------------------------

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