[vsnet-outburst 26819] ZTF21aanehlz: new SU UMa-type dwarf nova

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

Dear colleagues,

I have collected unfiltered CCD observations of ZTF21aanehlz on 7 nights between 2021, Feb 27th and Mar 10th. The object faded from mag 13.6 (CV) on Feb 27th to mag 15.0 (CV) on Mar 09th, without any apparent sign of superhumps in the light curve. My observations of Mar 09th showed a steady increase in brightness of ZTF21aanehlz, reaching mag 14.3 (CV) on Mar 10th, at which moment superhumps became visible.

My observations were made at CBA Extremadura Observatory, using a 0.40-m f/5.1 telescope and SX-46 CCD camera, mostly under clear skies. 

As mentioned above, regular superhumps with an amplitude of 0.14 mag became clearly visible on Mar 10th, establishing ZTF21aanehlz 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), yields a combined superhump period of 0.0665 +/- 0.0013d. The object was at mag 14.3 (CV) on Mar 10th.

The superhump profile shows no signs of a double-waved pattern, making it less likely that this is a WZ Sge-type dwarf nova (despite the large outburst amplitude of ~8 mag, and the long time for superhumps to develop). Follow-up observations are recommended to further track the evolution of the superhumps.

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

Best regards
Tonny

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