[vsnet-newvar 9800] Re: MGAB-V240: standstill interrupted by fading (AM CVn?)

Re: MGAB-V240: standstill interrupted by fading (AM CVn?)

If this identification is correct, repeated regular outbursts before 2020 were superoutbursts (with a supercycle of about 10-15 d). Faint, but unusual object.

I indeed detected superhumps during one of its outburst in 2018 June-July (time-resolved ZTF data on two nights). The period was 0.015822(9) d and an amplitude of 0.09 mag. This object is probably between dwarf nova-type CR Boo (Porb=0.017029 d) and novalike HP Lib (Porb=0.012763 d).