[vsnet-chat 1656] CW Mon---another CG CMa?

[bas@lowell.Lowell.Edu (Brian Skiff)]

     While getting coordinates for Wachmann's variables in SA 98 [vsnet-id 41],
I noticed that the position of the dwarf nova CW Mon in the Downes et al. 1997
catalogue differs slightly from that of the USNO-A2.0.  Further checking shows
that the AC2000 star catalogue has an observation of the star evidently in
outburst at mag. 12, versus mag. 16 in USNO-A.  A mag. 16 star would not have
been recorded on the Astrographic Catalogue plates.  Perhaps this is another
case similar to CG CMa.
     It wouldn't surprise me that the mag. 16 star was a companion to the CV,
and that it is much fainter in quiescence.  But the AC2000 position in what
seems to be an outburst state should be shifted in position relative to the
A2.0 location if the true CV lies some small distance away.  As with CG CMa,
astrometry needs to be obtained during a new outburst.  Both the POSS-I prints
and the POSS-II IIIa-F film show the mag. 16 star to be single as best I can
tell.  The Downes et al. and star-catalogue positions are shown below for
reference.


CW Mon

source        RA   (2000)   Dec
DWS97       6 36 54.53  +00 02 16.3
USNO-A2.0   6 36 54.55  +00 02 17.7
AC2000      6 36 54.47  +00 02 17.4


\Brian

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