[vsnet-alert 24730] ASASSN-20mm and MASTER OT J213908.79+161240.2: new WZ Sge-type dwarf novae

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

Dear colleagues,

 

I just completed a quick inspection of tonight's unfiltered CCD observations
of ASASSN-20mm and MASTER OT J213908.79+161240.2 (2020, Sep 26/27), obtained
(almost) simultaneously at CBA Extremadura Observatory, using a 0.40-m f/5.1
telescope and SX-46 CCD camera under clear skies. 

 

ASASSN-20mm - some preliminary conclusions: superhumps with an amplitude of
~0.46 mag are clearly visible in my light curve. Considering the large
outburst amplitude, this establishes ASASSN-20mm as a new WZ Sge-type dwarf
nova.  A period analysis using the ANOVA method (Peranso 3.0, in Beta test),
yields a superhump period of 0.073 +/- 0.002d. The object was at mag 16.4
(CV) on Sep 26th.

 

MASTER OT J213908.79+161240.2 - some preliminary conclusions: superhumps
with an amplitude of ~0.29 mag are clearly visible in my light curve.
Considering the large outburst amplitude, this establishes MASTER OT
J213908.79+161240.2  as a new WZ Sge-type dwarf nova.  A period analysis
using the ANOVA method (Peranso 3.0, in Beta test), yields a superhump
period of 0.056 +/- 0.001d. The object was at mag 16.2 (CV) on Sep 26th.

 

 

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

 

--

Tonny Vanmunster

CBA Belgium Observatory

CBA Extremadura Observatory

 <http://www.cbabelgium.com> www.cbabelgium.com

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www.peranso.com