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

[vsnet-alert 27960] PS1-3PI J063334.87-230546.4 = Gaia DR3 2924954955730613376 = TCP J06333486-2305449: superoutburst from a most likely AM CVn star
by Taichi Kato 02 Nov '23

02 Nov '23

PS1-3PI J063334.87-230546.4 = Gaia DR3 2924954955730613376 = TCP J06333486-2305449: superoutburst from a most likely AM CVn star Kiyota-san, Itoh-san and Josch Hambsch have reported observations. The data show superhumps with a period of 0.02942(2) d. Amplitude 0.043 mag. The low amplitude seems to suggest a low mass ratio, consistent with an AM CVn star. The data are still somewhat insufficient and more observations are needed.

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[vsnet-alert 27959] AT 2023veq (Vend55): bright nova candidate in M31
by FIDRICH Robert 18 Oct '23

18 Oct '23

Dear Friends, We have discovered a bright nova candidate in M31 on at around 18.6 magnitudes using 2x120s co-added images made om October 16.9870 UT with 0.32m telescope of the iTelescope.net network remotely at Nerpio, Spain with Luminance filter. AT 2023veq (Vend55) has significantly brightened in the 24 hours since it's discovery: by October 17.9082 UT the quest star has reached 17.7 magnitudes. More details: - http://vendegcsillagkereso.blogspot.com/2023/10/vend55-at-2023veq-bright-no… - https://www.wis-tns.org/object/2023veq - www.cbat.eps.harvard.edu/unconf/followups/J00433237+4138211.html Further photometric and spectroscopic follow-up observations are encouraged! Clear skies, Robert Fidrich and Tamas Tordai "Vendégcsillag-kereső" (Guest Star Hunter) team HAA/VSS

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[vsnet-alert 27958] ASASSN-23gr: new SU UMa-type dwarf nova
by Taichi Kato 14 Oct '23

14 Oct '23

ASASSN-23gr: new SU UMa-type dwarf nova Josch Hambsch has reported observations. The data show superhumps with a period of 0.06345(5) d. The amplitude is rather small (0.04 mag) and may be still growing.

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[vsnet-alert 27957] SDSSJ170810.31+445450.7 outburst
by Tadashi Kojima 11 Oct '23

11 Oct '23

object YYYYMMDD(UT) mag code SDSSJ170810.31+445450.7 20231010.397 133c Tko SDSSJ170810.31+445450.7 20231011.402 142c Tko Observer: Tadashi Kojima (Tsumagoi,Gunma, Japan) Instruments: f.l.=200mm,300mm lens + Canon EOS 6D

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[vsnet-alert 27955] Any news about T. Kato?
by Josch Hambsch 11 Oct '23

11 Oct '23

HI, any news about Taichi Kato? He has not been providing feedback on stars on VSNET since a couple of weeks. What happened to him? I hope we will get an answer from his collaborators. Looking forward to any reply. Best regards, Josch Hambsch

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[vsnet-alert 27954] SwiftJ1727.8-1613: superhumps?
by Taichi Kato 23 Sep '23

23 Sep '23

SwiftJ1727.8-1613: superhumps? This X-ray transient looks like to have started showing superhumps. An analysis of the data since Sep. 17 shows a signal at 0.2116(1) d (full amplitude 0.07 mag with multiple peaks in a period). Signals at P/2 or P/3 were weaker and the 0.2116-d period appears real. This signal apparently appeared in conjunction with the spectral/state transition (ATel #16247). Considering the case of ASASSN-18ey = MAXI J1820+070 (arXiv:2107.03681, Variable Star Bulletin 74), the current variation appears to be stage A superhumps. observers: Berto Monard, Itoh-san and Josch Hambsch

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[vsnet-alert 27953] X Ser in outburst
by Robert J. Modic 31 Aug '23

31 Aug '23

CCD Observations Object YYYYMMDD(UT) Mag Obs Chart Remarks SERX 20230830.635 15.62V MRV Henden MPO61; Err 0.04; Outburst Instruments: RCOS 24" w/FLI PL1603, AAVSONet (MPO61) Observer: Robert J. Modic (MRV)

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[vsnet-alert 27948] Swift J1727.8-1613: black-hole binary and V404 Cyg-like object ?
by Mariko Kimura 30 Aug '23

30 Aug '23

Swift J1727.8-1613: black-hole binary and V404 Cyg-like object ? Swift and MAXI detected an outburst in Swift J1727.8-1613. This is a candidate for a black-hole binary and possibly similar to V404 Cyg, a unique object known as a source of rapid variability. A few seconds variability was already found in X-rays. The most violent variability would be ~2 mag in several tens of min. This is very bright. Currently, ~13 mag. The position is (RA)17:27:46 (DEC)-16:12:53 reported by Swift. Follow-up observations are strongly encouraged. https://www.astronomerstelegram.org/?read=16205 https://www.astronomerstelegram.org/?read=16208 - Mariko Kimura at Kanazawa Univ. in Japan

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[vsnet-alert 27950] Re: SwiftJ1727.8-1613
by Taichi Kato 26 Aug '23

26 Aug '23

Re: SwiftJ1727.8-1613 Itoh-san reported time-resolved photometry (as TCP J17274332-1612188). Strong short-term variations comparable to V404 Cyg (more than 0.1 mag) were not detected.

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[vsnet-alert 27949] MASTER OT J183342.09+654019.1 superoutburst
by Taichi Kato 26 Aug '23

26 Aug '23

MASTER OT J183342.09+654019.1 superoutburst Superhumps of this object were observed in 2021 Apr., but not so well. YYYYMMDD(UT) mag observer 20230803.2927 17.662g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230805.3107 17.534g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230814.4402 17.555g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230822.4005 15.150g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) (forwarded message) === From: <andrew_simon(a)univ.kiev.ua> Date: Fri, 25 Aug 2023 22:43:27 +0300 Dear Dr. Taichi Kato, According to my observations in the Lisnyky observational station during the last two nights it looks like the object Gaia19cuu now in superoutburst. From the observations superhumps can be easily detected on the images attached to this letter. Data from the Gaia shows previous outbursts with the amplitude of 4-5 magnitudes (https://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19cuu/) Also data from Gaia Followup for 7 Jul 2019 submitted by Liam Hardy shows superhumps, due to these data I started to follow this object. ( https://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19cuu/followup) ZTF also detected multiple outbursts in the light curve as well as current outburst. https://lasair-ztf.lsst.ac.uk/objects/ZTF18aatluwz/ After analysing the data I found 0.068d period for 2023-08-23 and 0.077d period for 2023-08-24. But due to the relatively short duration of observations these determinations can be not precise. Obtained data relatively to the comp.star I also attached to this letter. This night it is cloudy in Kyiv so I have no possibility to continue observations. But I hope that the object will appear to be interesting for observations over the world. Best regards, Andrew Simon.

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