October 2024 - vsnet-campaign-dn - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-campaign-dn 17494] GOTO065054.49+593624.51: end of the type-E rebrighening
by Yusuke Tampo 31 Oct '24

31 Oct '24

GOTO065054.49+593624.51: end of the type-E rebrighening According to the most recent ATLAS forced photometry and AAVSO observations by Nikola Antonov, Arto Oksanen, and Klaus Wenzel, this object dimmed around 18th mag on 2024-10-30, likely an end of its type E brightening. As type-E-rebrighening systems typically show additional short-lived brightenings, daily snapshots are still encouraged. Best regards, Yusuke #ATLAS forced photometry #UTC mag band observer 20241004.59088 13.215 c atlas 20241004.59451 13.214 c atlas 20241004.61565 13.207 c atlas 20241004.63368 13.206 c atlas 20241006.61241 13.714 o atlas 20241006.63332 13.715 o atlas 20241006.63517 13.712 o atlas 20241006.64267 13.727 o atlas 20241008.60186 13.596 c atlas 20241008.60503 13.613 c atlas 20241008.62933 13.615 c atlas 20241008.64262 13.630 c atlas 20241012.56768 13.963 c atlas 20241012.57085 13.963 c atlas 20241012.57629 13.959 c atlas 20241012.59150 13.954 c atlas 20241016.57534 14.505 o atlas 20241016.57716 14.503 o atlas 20241016.59971 14.498 o atlas 20241016.60560 14.498 o atlas 20241020.46639 14.542 o atlas 20241020.47092 14.542 o atlas 20241020.47409 14.578 o atlas 20241020.50475 14.478 o atlas 20241024.52590 14.645 o atlas 20241024.52771 14.656 o atlas 20241024.53178 14.666 o atlas 20241024.54710 14.594 o atlas 20241030.54204 17.807 c atlas 20241030.55202 17.790 c atlas 20241030.55437 17.759 c atlas 20241030.56083 17.819 c atlas 20241030.56415 17.775 c atlas 20241030.56882 18.013 c atlas 20241030.57205 17.835 c atlas -- ---------------------------------------------- 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-campaign-dn 17493] GOTO065054.49+593624.51: type-E rebrightening WZ Sge star?
by Yusuke Tampo 23 Oct '24

23 Oct '24

GOTO065054.49+593624.51: type-E rebrightening WZ Sge star? Recent time-resolved observations reported to VSNET/AAVSO, especially those by Tonny Vanmunster, David Messier, Nikola Antonov, and Ian Sharp, show growing superhumps after its recovery from the short-lived dip around 2024-10-19. Using these time-resolved observations after the dip, the superhump period is obtained as 0.06323(2) d, consistent with previous Tonny's reports to VSNET alerts. These features suggest that this ongoing brightening event is likely a type-E rebrightening (dip caused by the disk transition from early to ordinary superhumps) and thus GOTO065054.49+593624.51 would be a new period bouncer candidate showing a WZ Sge-type dwarf nova outburst. For type-E rebrightenings and period bouncers, see.g. Kimura et al 2018 https://arxiv.org/abs/1803.03179 Further 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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[vsnet-campaign-dn 17492] GOTO065054.49+593624.51 - Regular superhumps with period of 0.0627 d
by tonny.vanmunster＠gmail.com 21 Oct '24

21 Oct '24

Dear colleagues Last night's (2024, Oct 20/21) unfiltered CCD observations of GOTO065054.49+593624.51, obtained at CBA Extremdara Observatory, show the emergence of regular superhumps allowing to precisely determine the superhump period of this system. Based on 175 observations obtained over 6.3 hours, and showing 4 distinct superhumps with an amplitude of 0.21 mag, I have now established the superhump period using ANOVA, GLS, Lomb-Scargle and PDM (Peranso 3.0) to be 0.0627 +/- 0.0004 d. This supersedes the preliminary superhump period values I published earlier on, which were based on early superhumps and more noisy datasets. 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-campaign-dn 17491] GOTO065054.49+593624.51 - Refined Superhump Period and First Rebrightening
by tonny.vanmunster＠gmail.com 21 Oct '24

21 Oct '24

Dear colleagues Following my announcement two days ago regarding the detection of (early) superhumps in the light curve of GOTO065054.49+593624.51, I now present an update based on observations from the AAVSO, and additional data contributed by CBA member David Messier and myself. In the first figure below, the AAVSO light curve of GOTO065054.49+593624.51 on the right with (cyan) polynomial fit illustrates a gradual decline in brightness over the first 13 nights, at a rate of approximately 0.11 mag per day. This is characteristic of a WZ Sge-type dwarf nova in the post-outburst decline phase, corresponding to the cooling and fading of the accretion disk. Notably, on October 19th, the object experienced a sudden drop in brightness to magnitude 15.7nearly 1 magnitude in just one nightfollowed by a rebrightening the next day. Rebrightenings are a hallmark feature of WZ Sge-type dwarf novae. These stars often undergo multiple rebrightenings, which is why continued monitoring of this object over the coming weeks is crucial. This phenomenon is likely associated with renewed accretion disk activity, potentially triggered by changes in the disk structure or mass transfer dynamics from the companion star. The top row in the same figure shows four sets of superhump observations by David Messier and myself. The bottom row presents the detrended versions of these same observations. These serve as the foundation for a more detailed period analysis, as demonstrated below. By combining these four observation sets into one dataset (second figure, top row left), I created a time window spanning 2.3 days, consisting of 430 observations. I then performed four different period analyses: Generalized Lomb-Scargle (top row right), PDM, ANOVA, and Lomb-Scargle (bottom row). All analyses revealed a dominant signal near 0.073 days, with the corresponding phase window displayed in the top row middle. The result is a refined superhump period of 0.0730 ± 0.0001 days, with an amplitude of 0.26 magnitudes. 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-campaign-dn 17489] GOTO065054.49+593624.51 is now optically confirmed as a new WZ Sge-type darf nova
by tonny.vanmunster＠gmail.com 18 Oct '24

18 Oct '24

Dear colleagues, I have just completed my analysis of unfiltered CCD observations of GOTO065054.49+593624.51, acquired on Oct 17/18, 2024 at the CBA Extremadura Observatory in Spain. The observations were made using a 0.40-m f/5.1 telescope and SX-46 CCD camera under moderately clear skies, though conditions were only favorable for about 2.2 hours. Since the discovery announcement by T. Killestein et al. on Oct 4, 2024 (ATEL #16842), I have been observing this object across multiple nights, during which no obvious modulations were visible in the light curve - until tonight, when GOTO065054.49+593624.51 exhibited superhumps for the first time. The superhumps displayed an amplitude of ~0.16 mag. Period analysis employing ANOVA, Lomb-Scargle, Generalized Lomb-Scargle, and PDM methods (Peranso 3.0), yielded a combined superhump period of 0.067 +/- 0.002d. Due to the limited observation window, this value remains uncertain, and I strongly recommend follow-up observations to further track the evolution of the superhumps. The object was at mag CV = 14.7 on Oct 18th. The superhump profile currently shows no indication (yet) of a double-waved pattern. The substantial outburst amplitude (> 8 mag), and the prolonged duration for superhumps to develop (approx. 13 days), in conjunction with the spectroscopic classification suggesting it is likely a WZ Sge-type CV (ATEL #16858), firmly establish this object as a new WZ Sge-type dwarf nova. Image calibration and photometry were done using my new photometry software Phoranso 1.0.5.5. I will be submitting my observations to AAVSO, CBA, and VSNET for further analysis. Best 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-campaign-dn 17488] ASASSN-24fy: new bright outburst from a known WZ Sge star candidate
by Yusuke Tampo 04 Oct '24

04 Oct '24

ASASSN-24fy: new bright outburst from a known WZ Sge star candidate ASAS-SN reported a new CV outburst candidate ASASSN-24fy discovered on 2024-10-1.99 at 11.01 mag. This system was indeed suspected to be a WZ Sge-type CV by Pala et al 2020 based on Gaia data. >Gaia J154008.28-392917.6 https://www.aavso.org/vsx/index.php?view=detail.top&oid=844362 https://ui.adsabs.harvard.edu/abs/2020MNRAS.494.3799P/abstract Time-resolved observations are encouraged to detect superhumps and confirm the outburst nature. 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-campaign-dn 17487] TCP J18173469+1803499: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 02 Oct '24

02 Oct '24

Dear colleagues I have just finished analysing my unfiltered CCD observations of TCP J18173469+1803499, obtained during 4 consecutive nights between 2024, Sep 28/29 and Oct 01/02 at CBA Extremadura Observatory using a 0.40-m f/5.1 telescope and SX-46 CCD camera under clear skies. This object was detected by the New Milky Way (NMW) survey Camera-2, operating at the Astroverty astrofarm in Russia, on Sep 27th. Superhumps started to emerge in my data set of 2024, Sep 29/30, and are now clearly present in my last set of observations obtained on 2024, Oct 01/02. That light curve shows regular superhumps with an amplitude of 0.11 mag, establishing TCP J18173469+1803499 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 0.0767 +/- 0.0026d. The object was at mag CV = 13.9 on Oct 02nd. Image calibration and photometry were done using my new photometry software Phoranso 1.0.5.1 which allowed me to simultaenously measure 10 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. Best 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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