ER Uma and RZ Lmi: Observations requested.

[Stewart John Bean]

Richard, Looks like you may have captured the start of the superoutburst. At the same time Steve Johnson made very similar observations reported to AAVSO.
A little later (UTC 2022/05/12 03:36:29 JD 2459711.65 ), using AAVSOnet New Mexico, I got a V magnitude of 13.1 which is in superoutburst territory. So it will probably remain bright for the next 5-10 days. If the superoutburst has started, it is 50 days from the last start – which is typical.

Regards

Stewart

[Stewart John Bean]

Definitely in superoutburst now. V mag is brighter than 13.0 last night.

[Stewart John Bean]

ER UMa has been observed through May by R Sargent, G Poyner, PB Withers, S Johnston, ND James yielding good coverage of the May 12 superoutburst. So far in this observing season, the superoutburst period has an average value of 45 days. This is fairly low compared to the graph presented in VSSC 188 one year ago ( see attachment).
Maybe the super-cycle period has a minimum value of about 40-45 days with occasional excursions to higher values? Only long term observations can illuminate this topic. The next superoutburst will be at the end of June if 45 days remains a reliable estimate.

RZ Lmi continues to show 26-27 days super-cycle periods consistent with a steadily increasing period length. The rate of change appears to be about 0.2 days per year as presented in VSSC190. Fewer observers follow RZ Lmi probably because it is a magnitude less bright than ER UMa but it compensates by always changing state. The next superoutburst may be on June 14.

My own observations are all via AAVSOnet or SLOOH. My thanks to those two organisations.

Stewart Bean

Attachments:

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   Updated-Zemko-graph-to-present.png
   

[Richard Sargent]

From my measurements on 14th and 15th June it looks like RZ LMi’s latest outburst was late on the 15th. Data is in the BAA Photometry database.

Attachments:

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   RZLMi-20220615.jpg
   

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