[vsnet-outburst 25866] ASASSN-20ms: new WZ Sge-type dwarf nova

Sat Oct 17 08:31:40 JST 2020

Dear colleagues,

ASASSN-20ms was detected in outburst on 2020, Oct 03.07 UT. I started observing this object on Oct 05/06, and have been doing unfiltered CCD photometry every single night till now, using  a 0.40-m f/5.1 telescope and SX-46 CCD at CBA Extremadura Observatory. Sky conditions were excellent during each of the 11 nights.

Superhumps with an amplitude of 0.26 mag started to appear on Oct 15/16 and were also prominently present during today's (Oct 16/17) session. Taking into consideration the long duration for superhumps to develop (12 days), this object is a new WZ Sge-type dwarf nova. A period analysis using the ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.0, in Beta testing), yields a combined superhump period of 0.0717 +/- 0.0003d. The object was at mag 15.7 (CV) on Oct 16th.

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

Follow-up observations are recommended to study this system.

Best regards
Tonny

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Tonny Vanmunster
CBA Belgium Observatory
CBA Extremadura Observatory
www.cbabelgium.com
www.peranso.com: Beta testers wanted