[vsnet-outburst 16631] SDSS J090221.35+381941.9: superhumps and mass ratio

[Taichi Kato]

SDSS J090221.35+381941.9: superhumps and mass ratio

   Pavol A. Dubovsky has reported observation on Mar. 13.
The brightness was same as on Mar. 12.  Short-term
modulations became stronger (~0.2 mag).  A period analysis of
Mar. 12-13 data yielded 0.03407(3) d, 1.5% longer
than the orbital period.  If it period represents
that of stage A superhumps, the mass ratio is estimated
to be 0.039.  According to eq. (9) in Tsugawa and Osaki
(1997), an AM CVn-type system with this period has
a secondary mass of 0.024 Msol.  The current estimation
is in good agreement with the predicted value.
Further observations are needed to confirm the period
and the identification of the superhump type.