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[vsnet-campaign-dn 2692] (fwd) on V3774 Sgr
(fwd) on V3774 Sgr
Date: Fri, 2 Aug 2002 18:40:45 +0900 (JST)
From: Hitoshi YAMAOKA <yamaoka@rc.kyushu-u.ac.jp>
Subject: [vsnet-id 680] on V3774 Sgr
Dear DN watchers,
I have examined many DSS images of V3774 Sgr. Several outbursts are
detected, so the identification is secure.
DSS2 1980 Jun 21 (JD 2444412) ------- A38W(I) q
DSS2 1981 May 13 (JD 2444738) ------- A38X(I) q
DSS1 1987 May 18 (JD 2446934) 17:50UT 060G(Vq) b
DSS1 1987 May 18 (JD 2446934) 18:40UT 068H(Vq) b
DSS1 1987 Aug 19 (JD 2447027) 11:39UT 06AN(Vq) q
DSS2 1988 Aug 19 (JD 2447393) ------- A35F(I) q
DSS2 1992 May 10 (JD 2448753) ------- A11U(R50) q
DSS2 1992 May 30 (JD 2448773) ------- A1X7(R40) o
DSS2 1992 Jul 21 (JD 2448825) ------- A1XG(R40) b
DSS2 1996 Aug 24 (JD 2450320) ------- A1P6(R5) q
DSS2 1996 Sep 9 (JD 2450336) ------- A1PA(R5) q
DSS2 1998 May 27 (JD 2450961) ------- A2QQ(R50) q
o : full outburst (comparable with the western star about 15.0 mag)
b : brighter than quiesient
q : on quisient magnitude
Vq: UK Schmidt quick V (4min exposure)
I : UK Schmidt (90min)
R* : UK Schmidt (*min)
-----
The GCVS and Downes' online catalog says:
V3774 Sgr 18:41:41.20 -32:54:36.1 14.7p - <19.0p
The position is rather good, but this minimum magnitude seems to be
underestimated. This CV is identified with cataloged stars:
USNO-A2.0 18:41:41.165 -32:54:33.62 b=17.5 r=17.4
GSC-2.2.1 18 41:41.083 -32:54:33.86 b=17.94 r=17.59 v=16.24
the b and r magnitudes in both catalogs are consistent with the
brightness of neighbour stars in the images in quisient. So, the
quiesient magnitude of V3774 Sgr is brighter than the GCVS value,
which would be around 17.5-18.0. GSC v magnitude would be corresponds
the value when this CV is somewhat brighter than quiesient, but not in
full outburst.
Sincerely Yours,
Hitoshi Yamaoka, Kyushu Univ., Japan
yamaoka@rc.kyushu-u.ac.jp
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