[vsnet-outburst 18682] ASASSN-15po: early superhumps, EI Psc-type or unusually short-P WZ Sge-type

[Taichi Kato]

ASASSN-15po: early superhumps, EI Psc-type or unusually short-P WZ Sge-type

   Gianluca Masi, Colin Littlefield and Maeda-san have
reported observations.  As already pointed out, the object
shows strong (0.08 mag in full amplitude) early superhumps
with double maxima.  The period is 0.050422(7) d.
Colin Littlefield also reported a low-resolution spectrum
showing a blue continuum.
Only two classes of objects with such a short period are
known: EI Psc-type or OV Boo (SDSS J150722.33+523039.8,
a halo CV?: Patterson et al. 2008 PASP 867, 510, and
Uthas et al. 2011 MNRAS 414, L89).
Since ASASSN-15po shows early superhumps, we can measure
the mass ratio (and know the evolutionary state) by detecting
stage A superhumps.  This is an exceptionally interesting
and unique possibility and please don't miss any single night
of superhump evolution!