1 research outputs found
OT J075418.7+381225 and OT J230425.8+062546: Promising Candidates for the Period Bouncer
We report on photometric observations of two dwarf novae, OT J075418.7+381225
and OT J230425.8+062546, which underwent superoutburst in 2013 (OT J075418) and
in 2011 (OT J230425). Their mean period of the superhump was 0.0722403(26) d
(OT J074518) and 0.067317(35) d (OT J230425). These objects showed a very long
growing stage of the superhump (stage A) and a large period decrease in stage
A-B transition. The long stage A suggests slow evolution of the superhump due
to very small mass ratios of these objects. The decline rates during the
plateau phase in the superoutburst of these objects were lower than those of SU
UMa-type DNe with a similar superhump period. These properties were similar to
those of SSS J122221.7-311523, the best candidate for the period bouncer.
Therefore, these two DNe are regarded as good candidates for the period
bouncer. We estimated the number density of period bouncers roughly from our
observations in the recent five years. There is a possibility that these WZ
Sge-type dwarf novae with unusual outburst properties can account for the
missing population of the period bouncer expected from the evolutionary
scenario.Comment: 24 pages, 10 figures, accepted for publication in PAS