[vsnet-alert 9436] V343 Ser (AS 289) variation and periodicity

[Taichi Kato]

   I have noticed that V343 Ser = AS 289 show large-amplitude
variations resembling a long-period Mira (data from ASAS-3).
The amplitudes of variations were 1.0-1.5 mag in V.

   The maxima were around
(the phases were against Fekel et al. 2001, AJ 121, 2219,
P=450.5, phase zero corresponds to periastron)

  JD             phase
2452410           0.74
2452880 (bright)  0.78
2453350: (gap)    0.83
2453860           0.96

  VSOLJ data (+ Takamizawa et al.)

2449950           0.28
2450300           0.06
2451000:          0.6

   An analysis of the ASAS data has yield a period of 497 d.
Although the photometric period seems to have a relation with
the spectroscopic period, the phase and period do not match
each other very well.  The ASAS light curve, however, looks
relative regular as that of a symbiotic Mira.  Many questions
naturally arise:

1) if the variation is from a Mira star, it would be rather
unusual to see such amplitudes in a outbursting symbiotic binary.
Why didn't see similar variations (despite small number of
past observations) before the 1994 outburst?

2) if it is a Mira star, could pulsations affect the
interpretation of orbit determination?

3) the presence of such a period slightly exceeding the orbital
period is seen in Z And and AG Dra.  Could they be from similar
phenomena?

4) BX Mon is known to show large-amplitude Mira-like semiperiodic
variations (apparently from orbital modulation).  Is similar
mechanism acting in an eccentric V343 Ser?

   Since V343 Ser is favorably situated, continued observations
will make sense in the absence of ASAS operation.