[vsnet-alert 25213] MN Lac possible superoutburst

[Denis Denisenko d.v.denisenko@gmail.com via vsnet-alert]

This SU UMa-type dwarf nova was detected in an outburst by the Zwicky
Transient Facility (ZTF) on January 6th. 35 hours later Xingming
Observatory Sky Survey (XOSS) observed it and reported to TNS on January
8th as AT 2021rg = XM33HT.

MN Lac = ZTF18aaznfkp = AT 2021rg
  20210104.1213  19.09g  ZTF
  20210104.1371  18.44r  ZTF
  20210106.1138  15.96r  ZTF Outburst!
  20210106.1425  15.90g  ZTF Outburst!
  20210107.5554  15.82C  Xingming Observatory
  20210108.1422  15.80g  ZTF

Gaia EDR3 position: 22 23 04.67 +52 40 58.2
ZTF Lasair real-time light curve and snapshots:
https://lasair.roe.ac.uk/object/ZTF18aaznfkp/
Transient Name Server entry: https://www.wis-tns.org/object/2021rg

Range from ZTF data: 15.7-21.2g. ZTF DR4 light curve (Masci et al., 2019):
http://scan.sai.msu.ru/~denis/MNLac-ZTF-DR4-LC.gif

Zoomed ZTF light curve of August 2018 superoutburst:
http://scan.sai.msu.ru/~denis/MNLac-Aug2018SO.gif

Since the current outburst stands for more than 48 hours, this should be a
superoutburst. According to [vsnet-alert 20283], two superhumps were
recorded by Tonny Vanmunster in 2016. The approximate period is 0.081(1) d.
Time-resolved photometry is encouraged to improve the period value and to
follow its changes.

Denis Denisenko