[vsnet-alert 24361] ASASSN-20gd: 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 Jun 14 23:11:57 JST 2020

Dear colleagues,

I have just finished analysing my unfiltered CCD observations of ASASSN-20gd, obtained during 2 consecutive nights, June 12/13 and June 13/14 at CBA Extremadura Observatory, using a 0.40-m f/5.1 telescope and SX-46 CCD camera.

On both nights, low amplitude superhumps (0.07 mag) were visible, establishing ASASSN-20gd as a new SU UMa-type dwarf nova. Combining my own observations with June 12/13 and 13/14 observations of Josch Hambsch, I performed a period analysis using the ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.0, under development) methods. This yields a combined superhump period of 0.0559 +/- 0.0004d. The object was at mag 14.9 (CV) on Jun 14th. It is declining in brightness at approx. 0.14 mag/d.

More pronounced superhumps may still develop in the days to come, so continued observations of this object are highly recommended.

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

Best regards

Tonny Vanmunster
CBA Belgium Observatory
CBA Extremadura Observatory

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