[vsnet-alert 22559] ASASSN-18ey = MAXI J1820+070: rapid fading and period change

[Yasuyuki WAKAMATSU]

ASASSN-18ey = MAXI J1820+070: rapid fading and period change

Geoff Stone, Tonny Vanmunster, Michael Richmond, Stephen Brincat,
Crimean Astrophys. Obs. team, Josch Hambsch, Kyoto U. team, Itoh-san,
Peter Nelson, Vihorlat observatory team (Pavol A. Dubovsky, Tomas
Medulka) and
Alexandra Zubareva reported further observations.

The fading rate of the object increases since September 8, from 0.01
mag/day to
0.04 mag/day now. The current magnitude is about 14.1 mag. The O-C diagram
indicates that the superhump period seems to have changed on around July
29,
from 0.68764(2) d to 0.68841(3) d now. The superhump amplitude also
started to
increase on August 24. The superhump amplitude is now about 0.15 mag.

Continuous observations are encouraged to monitor the next behavior.