[vsnet-alert 2676] Re: CG CMa astrometry

[Patrick Schmeer <extpasc@rz.uni-sb.de>]

From vsnet-alert 2670:  

> CG CMa astrometry

>    From the CCD image taken by K. Matsumoto and me last night, we have
> obtained astrometry of CG CMa.

>    07h 04m 05s.28  (2000.0)
>    -23o 45' 34".2

>    Using 8 GSC stars, mean residual 0".3.  The position seems to be slightly
> (a few arcsec) different from the USNO star, which has been suggested to be
> the quiescent counterpart of CG CMa.

>    USNO0600.02563019 070405.022 -234534.36 (2000.0) 16.5 17.3

>    We would be very grateful to know independent astrometry.

> Regards,
> Taichi Kato and Katsura Matsumoto

-------------------------------------------------------------------------------
Arne Henden got the following results:
R.A. 07h04m05.21s  Decl. -23d45'34.1"  (J2000.0)  V= 14.089, B-V= -0.081
There is no other star very close to the USNO star in Henden's table. I 
suppose this USNO star is identical with the star (mpg= 15.9) that is marked 
on the POSS chart in Duerbeck's nova catalog.
Unfortunately I have not yet seen any CCD images of CG CMa in outburst.
Could it be possible that CG CMa and the USNO star are very close companions?
An outburst amplitude of only 2-3 magnitudes (if CG CMa and the USNO star are 
identical) seems to be very small for a CV (dwarf nova?) with such rare 
outbursts.
 
Regards,
Patrick

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