[vsnet-alert 24487] RX J0044.3+4134 (aka AT 2020plo): emergence of early superhumps - likely new WZ Sge-type dwarf nova

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

Dear colleagues,

Starting July 22nd, 2020, I have conducted nightly unfiltered CCD observations of RX J0044.3+4134  using my 0.40-m f/5.1 telescope and SX-46 CCD camera at CBA Extremadura Observatory. RX J0044.3+4134 is also known as AT 2020plo, and was detected in outburst by ZTF on July 15th (see ATEL #13869). Initially, it was considered to be a recurrent nova in M31, but then spectroscopically was identified as a galactic dwarf nova (see ATEL #13883).

The object has been varying between mag 15.8 (CV) and mag 16.0 (CV) over the past 6 nights, showing very small amplitude, irregular variations. However, last night's (Jul 27/28) observations clearly show the emergence of what appears to be early superhumps (double-waved) with an amplitude of approx. 0.16 mag, most likely pointing to the WZ Sge-type nature of this dwarf nova - to be confirmed through further observations. 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 0.0705 +/- 0.0028d, but given the short baseline this value obviously needs to be refined over the next nigths.

The object was at mag 16.0 (CV) on Jul 28th.

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

Follow-up observations evidently are very highly recommended to study the further evolution of this interesting object.

Best regards
Tonny

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