[vsnet-alert 22740] ASASSN-18yi: stage C superhumps?

[Yasuyuki WAKAMATSU]

ASASSN-18yi: stage C superhumps?

Josch Hambsch and Berto Monard reported further observations.
The O-C diagram indicates the object now might show stage C
superhumps. The stage transition seems to be occurred on
November 16. The amplitude of superhumps is about 0.6 mag and
this is larger than that of stage A ones. Our study of eclipses
suggests that the inclination of the system is 76 °. The disk radius is
estimated to be the range of 0.28a-0.35a ("a" is a binary separation)
and this value is smaller than the 3:1 resonance radius, 0.44a, with
the mass ratio of 0.34. This analysis indicates the superoutburst of
the object might not be a SU UMa-type superoutburst. The current
magnitude is 18.8 mag.
Further observations are needed to confirm the current superhump
stage.