[vsnet-outburst 25491] ASASSN-19fy: new long-period SU UMa-type dwarf nova

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

Dear colleagues,

I have just finished a first analysis of my (ongoing) unfiltered CCD observations of ASASSN-19fy, obtained tonight 2020, Aug 11/12 at CBA Extremadura Observatory, using a 0.40-m f/5.1 telescope and SX-46 CCD camera under clear skies. My observations were triggered by [vsnet-alert 24519], suggesting the possible SU UMa-nature of this object.

Large amplitude superhumps (0.27 mag) are clearly visible in my CCD observations, establishing ASASSN-19fy 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 long superhump period of 0.0889 +/- 0.0033d. The object was at mag 14.2 (CV) on Aug 12th.

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

Follow-up observations are recommended to refine the superhump period.

Best regards
Tonny

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