[vsnet-alert 9321] On GW Lib periods

[Taichi Kato]

Dear all,

   A preliminary analysis of the early part (before full
superhumps appeared) of the light curve has yielded a period
of 0.05429(2) d.  This period may represent the period of early
superhumps.  If this is the case, the period in 
[vsnet-alert 9316] (April 20 and 21) referred to that of
early superhumps.

   If this period is the true orbital period, the fractional
superhump excess becomes 0.9 %, a comfortable value for
a WZ Sge-type dwarf nova.

   However, the value is inconsistent with Thorstensen et al.
(2002), who determined the spectroscopic period of 0.05332 d.
The data up to now seem to suggest either possibilities:
(a) a WZ Sge-type system with an unusually large fractional
superhump excess (or q), or (b) the true orbital period is
closer to the superhump period, and Thorstensen et al.
detected a signal close to, but is different from, the orbital
period (negative superhumps??).  Difficult to explain -- and
an intriguing possibility.

   Further observations to precisely determine the superhump
(and hopefully an independent measurement of orbital) period
is naturally strongly encouraged, since the superhump period was
determined from a short baseline, and we don't know how the
period further evolves.