[vsnet-alert 24669] ASASSN-17dd: SU UMa-type dwarf nova and period determination

[Tonny Vanmunster tonny.vanmunster@gmail.com via vsnet-alert]

Dear colleagues,

Further to the announcement in vsnet-outburst 25662, I herewith report my independent detection of superhumps in ASASSN-17dd. I made my unfiltered CCD observations yesterday (Sep 07/08, 2020), but due to travel could only now analyse the results. My session was 3.8h long and carried out at CBA Extremadura Observatory, using a 0.40-m f/5.1 telescope and SX-46 CCD camera under clear skies. 

Superhumps with an amplitude of 0.15 mag are clearly visible in the light curve. 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 0.0733 +/- 0.0010d. The object was at mag 15.0 (CV) on Sep 07th.

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

Best regards
Tonny

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Tonny Vanmunster
CBA Belgium Observatory
CBA Extremadura Observatory
www.cbabelgium.com
www.peranso.com