[vsnet-alert 22275] ASASSN-18ey (MAXI J1820+070): gradually change of superhump period

[Yasuyuki WAKAMATSU]

ASASSN-18ey (MAXI J1820+070): gradually change of superhump period

Itoh-san, Stephen Brincat, Geoff Stone, Tonny Vanmunster,
Ian Miller, Domenico Licchelli, Michael Richmond, Lew Cook
and Josch Hambsch reported further observations.

The superhump period of this object is now about
0.68856(9) d and gradually shortened. The amplitude is still
large, about 0.6 mag. The change of superhump period might
imply that this object shows the stage A-B transition of
superhumps if this is similar in the case of SU UMa-type dwarf
novae. This object is now in about 13.3 mag and it seems to get
slightly dark, suggesting that this object reached the secondary
maximum of brightness.

Further observations are strongly encouraged to detect the
following period change, and multicolor observations will be
helpful to clarify light sources of the accretion disk.