[vsnet-alert 7359] V359 Cen: system analogous to EF Peg or V725 Aql?

[Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>]

V359 Cen: system analogous to EF Peg or V725 Aql?

    Up to now, only superoutbursts have been detected with a mean interval
of ~1 year.  Although this might be resulted from the difficulty in
detecting fainter normal outbursts, the apparent lack of normal outbursts
may be a result of a low mass-transfer rate.  This possibility may explain
the long persistence of the signal following the superoutburst (now
unambiguously identified!) in 1999 (Woudt et al. (2001) MNRAS 328, 159),
which had a period close to what it presently observed.  Only a few systems
(WZ Sge being the best example) are known to show such a long persistence
of the "late superhump" signal.

    Systems with similar outbursts and orbital parameters include EF Peg
and V725 Aql, both of which show unusually infrequent outbursts for their
superhump period. [References: EF Peg: Kato (2002) PASJ 54, 87;
V725 Aql: Uemura et al. (2001) PASJ 53, 539].  Both stars have (at least
on one occasion) shown virtually zero period changes in contrast to
the "textbook" negative period derivatives in ordinally SU UMa-type
dwarf novae.

     Further observations of superhumps in V359 Cen throughout the current
superoutburst are therefore urgently requested to determine the period
derivative; accurate measurement of times of superhump maxima (at least
once per night) is a very recommended protocol.  V359 Cen may show
a rebrightening, as was observed in V725 Aql.  Nightly monitoring
following the present superoutburst is also highly encouraged.

Regards,
Taichi Kato
VSNET Collaboration team

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