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Images taken last night showed the reported object at a constant and not
modulating brightness of around 14.2CR measured against reference stars from
uCAC1.
Basic astrometry showed this object at position (2000)
17 59 16.53 -42 35 07.3
which is very likely coinciding with a star from the uSNO-A2.0
catalogue at position
17 59 16.521 -42 35 06.85
This catalogue gives 18.3B / 17.5R as magnitudes.
The following unfiltered CCD observations are reported:
NSV 09923 20030628.810 14.3CR MLF
NSV 09923 20030628.861 14.2CR MLF
Berto Monard
Bronberg Observatory / CBA Pretoria
----- Original Message -----
Sent: Sunday, June 29, 2003 3:39 AM
Subject: [vsnet-alert 7787] NSV 09923
outburst!
NSV 09923 outburst!
As reported by Rod
Stubbings in [vsnet-outburst 5689], a star has
brightened at the position
of NSV09923.
> A star has brightened at the position of NSV09923 can
someone confirm?
>
> NSV09923
030628.446 140 Stu.RASNZ
> NSV09923 030628.465
140 Stu.RASNZ (vsnet-obs 45665)
This object was
recognized during the identifications of NSV objects
against ROSAT X-ray
source (Kato 2000, vsnet-id-rosat 11). The proximity
of the ROSAT
position to the NSV position suggests that the object may be
a dwarf nova,
as we have seen in an excellent case in NSV 10934.
The
"outburst" has been confirmed by Berto Monard (vsnet-outburst
5691):
> A star has obviously brightened. Its position is somewhat
South of the
> one given by the SIMBAD database. It's difficult to
estimate the
> brightness but it could be around magnitude 14CR
(compared to about 16
> on the DSS image).
The
object has been monitored by Rod Stubbings since 2001 (54
observations),
and this is the first outburst
detection.
These observations seem to have confirmed the
dwarf nova-type (or other
kind of CV-type) nature of this object.
Since the ROSAT position is slightly
south to the NSV original position,
Berto's finding seems to further support
the
identification.
NSV: 175917.1 -423504 (2000.0) NSV09923 ?
14.2 (15.5 P
ROSAT: 175914.4 -423528 (2000.0) 1RXS-F_J175914.5-423529 0.095
0.83 0.08
Further observations (time-resolved photometry
and spectroscopy) are
most urgently encouraged! We will prepare a
special page when Berto's
(or other observer's) images becomes
available.
Regards,
Taichi Kato
VSNET Collaboration
team
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