[vsnet-alert 24229] MASTER OT J204627.96+242218.0: new SU UMa-type dwarf nova

Tonny Vanmunster tonny.vanmunster@gmail.com via vsnet-alert vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp
Sun Apr 26 17:42:26 JST 2020

Dear colleagues,

I have just finished analysing my unfiltered CCD observations of MASTER OT J204627.96+242218.0, obtained this night (2020, Apr 25/26) at CBA Belgium Observatory, using a 0.40-m f/10.0 telescope and STT-3200ME CCD camera, under a very clear sky.

The resulting lightcurve clearly shows the presence of superhumps, with an amplitude of 0.26 mag, hence establishing MASTER OT J204627.96+242218.0 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, under development), yields a combined superhump period of 0.0600 +/- 0.0031d. The object was at mag 15.3 (CV) on Apr 26th.

Thanks to Yutaka Maeda-san for reporting the outburst detection.

It is rather surprising that the SU UMa nature of this dwarf nova was not reported before. The AAVSO database contains outburst observations of this object on Jul 27th, 2017, showing superhumps. The observations were made by Spanish AAVSO observers Francisco Campos and Teofilo Arranz.

I will send my observations to AAVSO, CBA and VSNET for further analysis.

Follow-up observations are highly recommended to refine the superhump period and to study its further evolution.

Best regards

Tonny Vanmunster
CBA Belgium Observatory
CBA Extremadura Observatory

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