[vsnet-alert 25285] DDE 35 = 1RXS J105503.5+681208 outburst

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

DDE 35
  20210114.3973  19.13g  ZTF (Masci et al., 2019)
  20210116.4586  19.71r  ZTF
  20210117.1300  17.34G  Gaia
  20210117.2041  17.84G  Gaia
  20210118.4137  17.26r  ZTF
  20210118.4320  17.19g  ZTF

This variable in Ursa Major is showing very interesting behavior. Gaia
light curve for the last 6+ years looks like the fading after bright long
outburst in Nov. 2014 - Apr. 2016, then a dip in July 2016 - Feb. 2017,
then a "super rebrightening" in Apr.-Oct. 2017 followed by another dip in
Nov. 2017 - July 2018, then rebrightening in Aug.-Nov. 2018 with the final
return to the quiescent level at 19.3 which was never reached in 2014-2018.

In April-May 2020 there was a double-peaked outburst in both Gaia and ZTF
data. All in all, it looks much like the extended copy of TCP
J21040470+4631129 = V3101 Cyg superoutburst, but with a smaller amplitude
and slowed down by 4-5 times.

Gaia light curve: http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia16aoy/

ZTF Lasair data: https://lasair.roe.ac.uk/object/ZTF18accnpno/

In April 2020 there was a report from the CrAO team of the large-amplitude
(0.4m) superhumps with P=0.116(3) d and somewhat atypical profile, quoting
T. Kato from [vsnet-alert 24074]. However, J. Thorstensen has obtained for
DDE 35 the spectroscopic period P=0.1477(5) d in 2018 (Feb. 28, private
communication).

Unfortunately there is no ZTF data for this star in the last 4 days.
Nightly snapshots are very much desirable to see where the star decides to
go now. Gaia data from Jan. 17 also suggest the large-amplitude rapid
variability (0.5m in 1.8 hr).

Denis Denisenko
http://scan.sai.msu.ru/~denis/VarDDE.html