ATOJ277.8818+42.0389 = SDSS J183131.63+420220.2 showing large-amplitude variations

This object has been almost in novalike state in 2017-2022, with a sudden fading similar to AM CVn stars. Apparently much more variable in this season.

YYYYMMDD(UT) mag observer 20230420.4230 16.973zg (ZTF Alert DC mag (Masci+ 2019)) 20230420.4746 17.352zr (ZTF Alert DC mag (Masci+ 2019)) 20230422.4469 17.063zg (ZTF Alert DC mag (Masci+ 2019)) 20230424.4703 17.780zg (ZTF Alert DC mag (Masci+ 2019)) 20230426.4308 17.156zg (ZTF Alert DC mag (Masci+ 2019)) 20230426.4682 17.559zr (ZTF Alert DC mag (Masci+ 2019)) 20230503.4260 17.421zr (ZTF Alert DC mag (Masci+ 2019)) 20230511.4679 17.046zg (ZTF Alert DC mag (Masci+ 2019)) 20230514.3608 17.029zg (ZTF Alert DC mag (Masci+ 2019)) 20230514.4129 17.501zr (ZTF Alert DC mag (Masci+ 2019)) 20230517.4047 18.079zr (ZTF Alert DC mag (Masci+ 2019)) 20230519.4528 18.134zr (ZTF Alert DC mag (Masci+ 2019)) 20230521.3666 19.024zg (ZTF Alert DC mag (Masci+ 2019)) 20230521.4234 19.500zr (ZTF Alert DC mag (Masci+ 2019))