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

[vsnet-newvar 10215] ASASSN-23gr: new SU UMa-type dwarf nova
by Taichi Kato 13 Oct '23

13 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-newvar 10214] SwiftJ1727.8-1613: superhumps?
by Taichi Kato 22 Sep '23

22 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-newvar 10213] Update ephemeris for ASASSN-14ix (regarding Bruch's paper)
by Taichi Kato 30 Aug '23

30 Aug '23

Update ephemeris for ASASSN-14ix (regarding Bruch's paper) In relation to: https://arxiv.org/pdf/2308.16106.pdf > The only available information consists of informal > communications (Hambsch 2014a,b) reporting deep eclipses > and an orbital period of 0.1444610954(1) d > The formal accuracy of this value must be grossly overestimated. > It would lead to an error of eclipse epochs of merely 2.2 sec over a > time base of 100 years! I updated the ephemeris using the same data (not using TESS). Min(BJD) = 2457008.54251(3) + 0.144461097(4) E The value posted to vsnet-alert was a result of quick analysis (not involving a sufficient number of iterations), but was not "grossly overestimated". The MCMC chain is well-mixed and there is no anomaly in the posterior probability. The author needs to know that the error can be much smaller than one would assume naively or smaller than the exposure time, particularly in eclipsing systems with rapid ingress and egress, and if long-baseline collective data are analyzed. It is also not apparent in this paper who was responsible for the accuracy of this value.

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[vsnet-newvar 10212] Re: SwiftJ1727.8-1613
by Taichi Kato 25 Aug '23

25 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-newvar 10211] MASTER OT J183342.09+654019.1 superoutburst
by Taichi Kato 25 Aug '23

25 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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[vsnet-newvar 10210] TCP J16420534+8156125 ordinary superhumps
by Taichi Kato 12 Aug '23

12 Aug '23

TCP J16420534+8156125 ordinary superhumps The most recent observations by Itoh-san on Aug. 12 showed ordinary superhumps.

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[vsnet-newvar 10200] TCP J16420534+8156125 bright likely dwarf nova
by Taichi Kato 09 Aug '23

09 Aug '23

TCP J16420534+8156125 bright likely dwarf nova http://cbat.eps.harvard.edu/unconf/followups/J16420534+8156125.html 164209.215 +815556.26 (2000.0) Gaia_DR2_1710719047756794368 plx=1.700(0.682) dismod=8.8 pmra=-13.473(1.951) pmdec=25.647(2.137) G=20.587 BP=20.469 RP=20.125 164209.212 +815556.28 (2000.0) Gaia_EDR3_1710719047756794368 plx=1.896(0.572) dismod=8.6 pmra=-13.299(0.746) pmdec=25.917(0.841) G=20.494 BP=20.613 RP=20.253

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[vsnet-newvar 10208] TCP J16294031-4022063: superhump period
by Taichi Kato 06 Aug '23

06 Aug '23

TCP J16294031-4022063: superhump period Superhump period is 0.05378(1) d (shorter one-day alias is less likely considering the Porb distribution of CVs). Observers: Josch Habmsch

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[vsnet-newvar 10207] PNV J19030433-3102187: superhump period
by Taichi Kato 06 Aug '23

06 Aug '23

PNV J19030433-3102187: superhump period The object apparently started to show superhumps on Aug. 1. The current mean period is 0.05777(2) d (amplitude 0.15 mag). Observers: Itoh-san, Josch Habmsch, Greg Bolt

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[vsnet-newvar 10206] TCP J16420534+8156125: period of early superhumps
by Taichi Kato 06 Aug '23

06 Aug '23

TCP J16420534+8156125: period of early superhumps P=0.06087(1) d. Typical double-wave modulations Amplitude 0.06 mag. The period suggests a WZ Sge star with multiple rebrightenings. Observers: Itoh-san, Stephen Brincat, Kiyota-san, Magnus Larsson, Tonny Vanmunster.

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