[vsnet-outburst 25007] ASASSN-17ls: new SU UMa-type dwarf nova

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

Dear colleagues,

I have just finished analysing my unfiltered CCD observations of ASASSN-17ls (see also vsnet-alert 24186), obtained last night (2020, Apr 16/17) 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 0.20 mag, hence establishing ASASSN-17ls 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 0.0873 +/- 0.0023d. The object was at mag 14.5 (CV) on Apr 16th.

Observations will be sent 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

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