[vsnet-alert 24194] ASASSN-17ls: new SU UMa-type dwarf nova

Tonny Vanmunster tonny.vanmunster@gmail.com via vsnet-alert vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp
Fri Apr 17 19:16:02 JST 2020

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 Vanmunster
CBA Belgium Observatory
CBA Extremadura Observatory

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