[vsnet-campaign-dn 17491] GOTO065054.49+593624.51 - Refined Superhump Period and First Rebrightening
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/>
Hi, This is a great and well illustrated post by Tonny. It shows the capabilities acquired by dedicated observers and his 'peranso' is a more than useful analysing tool. The 0.11mag/day decline rate seems to be a recurring feature of ugwz systems but I would have expected it to be somewhat different for systems with longer Porbs. This seems not to be the case. Someone please enlighten my limited understanding... Regards, Berto Monard / CBA KKO Calitzdorp / South Africa On Mon, Oct 21, 2024 at 1:05 AM <tonny.vanmunster@gmail.com> wrote:
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 15.7—nearly 1 magnitude in just one night—followed 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
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Tonny Vanmunster
CBA Belgium Observatory
CBA Extremadura Observatory
PERANSO : The Light Curve and Period Analysis Software
PHORANSO: Photometric Reduction and Analysis Software *** NEW ***
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Berto Monard -
tonny.vanmunster＠gmail.com