[vsnet-alert 14958] 1RXS J210201.7+335932 so far

[Denis Denisenko]

Further to [vsnet-alert 14935] I have obtained two more observations
of this variable in Cygnus with the Bradford Robotic Telescope on Sep.
24 and Sep. 30. All images were unfiltered with 60-sec exposures.
Using USNO-A2.0 1200-16836883 (21 01 45.51 +34 02 24.6) with R=13.3 as
a reference star, the following magnitudes were measured:

  20120913.057 <195C  BRT
  20120920.018  171CR BRT
  20120924.017  166CR BRT
  20120930.024  179CR BRT

Enrique de Miguel has obtained 4 nights of photometry. The amplitude
of variability is 1.2m (16.8-18.0), and the most likely orbital period
is 0.1178d (2.83h), in the CV period gap. It is not clear yet if the
variable is a dwarf nova or a polar. Based on the high
X-ray-to-optical flux ratio it is most likely a magnetic CV. If so,
the current high state should last longer than two-three weeks. But if
it is a dwarf nova, it should start fading quickly very soon. This is
why a nightly monitoring is required. Since the orbital amplitude is
so high and the period is long enough, 5-min exposures with 25-30 cm
telescopes (or even smaller ones in excellent observing sites) are
enough to obtain the general light curve.

There are indications of the possible short-period (~8 min) signal, as
would be expected for the intermediate polar. But this variability can
only be confirmed by the observations with the larger amplitude
telescopes using 60-sec (or shorter) exposures.

Best regards,

Denis in Moscow