[vsnet-alert 7535] UW Pic in active state

["Berto Monard" <LAGMonar@csir.co.za>]

Southern polar UW Pic is showing violent oscillations! 

From periodic monitoring it was clear that UW Pic had reached a stage
of elevated brightness, from the usual mag 16-17 to around 15 and
below.

Snapshot CCD measurements at CBA-Pretoria during 2001-2002 showed this
polar at magnitudes in the range 16-17 and sometimes around 15.7.
Two recent observations, after the solar conjunction, gave the
following magnitudes:

UW Pic 20020919.100 (UT)   15.0CR
UW Pic 20020924.093 (UT)   14.7CR

Timeseries photometry in unfiltered mode, performed during the latter
part of last night (Sep 24-25), showed strong oscillations between
magnitudes 14.3 and 15.6 with a periodicity of 0.0425d. The photometric
measurements were done with a cycle period of 1 minute using the CBA
Pretoria set-up of which the observing details follow:. 

The on-line cv atlas describes UW Pic (Pic1, RX J0531-4624) as an AM
Her star with a magnitude range between 16.4V-17.2V and a period of
0.09268 (1994).


It can be expected that fast photometry at the 10 sec level (and below)
will reveal much more detailed action. Unfortunately this cannot be done
at the Bronberg observatory.

With my best regards,

Berto

CCD observations of 19-25 September 2002 
observer: Berto Monard  MLF, Pretoria, South Africa
Bronberg observatory / CBA Pretoria
location: -25 º 54' 48", 28º 26' 44"E, altitude 1590m
instrumentation: LX200 12" f/4.2 with ST-7E, unfiltered
conditions: clear with moon

Note: Reported CR magnitudes result from differential photometry to
non-red
comparison stars with R magnitudes (directly or derived) from published

photometric data or traceable to UCAC1 (comparison stars selected from
USNO-A2.0 data on the basis of non-red colour and reliability of the
data).

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