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[vsnet-campaign-news 65] AstroAlert: V551 Sgr rare outburst
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Rare Outburst of an Large-Amplitude Dwarf Nova
V551 Sagittarii
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Andrew Pearce (Australia) reports that the dwarf nova V551 Sgr is
undergoing a relatively rare outburst. The last outburst was in 2000
April (mv=13.9, Rod Stubbings). The object has been claimed to be a
possible WZ Sge-like object (just as AL Com), based on its large outburst
amplitude (the minimum reaching the 20th magnitude). One the occasion of
the 1998 October outburst, Gordon Garradd obtained time-series photometry
on two nights, but the short visibility hindered a firm conclusion on the
existence of superhumps. The present outburst, if confirmed, would
provide an excellent opportunity to throughly study this still poorly
understood dwarf nova. The VSNET Collaboration team lists the object
as one of prime targets in the morning sky.
YYYYMMDD(UT) mag observer
20010425.603 <140 (R. Stubbings)
20010426.860 <150 (A. Pearce)
20010429.613 <140 (R. Stubbings)
20010429.851 <153 (A. Pearce)
20010430.581 <140 (R. Stubbings)
20010430.824 <153 (A. Pearce)
20010501.608 <140 (R. Stubbings)
20010502.856 <153 (A. Pearce)
20010503.828 <153 (A. Pearce)
20010514.515 <140 (R. Stubbings)
20010515.574 <140 (R. Stubbings)
20010522.619 <152 (A. Pearce)
20010523.821 <152 (A. Pearce)
20010525.451 <140 (R. Stubbings)
20010526.833 144 (A. Pearce)
V551 Sgr is located at: 18h 00m 56s.2, -34o 35' 42" (J2000.0)
Gordon Garradd has kindly provided his CCD image of V551 Sgr taken in
1998 October. The image is available at:
http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/DNe/V551_Sgr/v551sgr.jpg
http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/DNe/V551_Sgr/v551-01.fits
Regards,
Taichi Kato
VSNET Collaboration team
We have been undertaking on photometric campaigns on several super-
outbursting dwarf novae and peculiar variable stars. News and call for
observations on these objects will be issued on our regular weekly
"News from VSNET" bulletins. Those who immediately need information
should make an access to the VSNET website, and click on VSNET campaign
list.
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VSNET (Variable Star Network) is an international variable star observing
network, covering various areas of novae, supernovae, cataclysmic variables
(CVs), X-ray transients, and other classical eruptive, pulsating, and
eclipsing variables. VSNET is one of invited contributing organizations
to the SkyPub AstroAlert system.
VSNET Home Page: http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/
CCD observations of such targets are a relatively easy task for a 20-40cm
telescope; simply take as many CCD frames (with exposure times 10-30 sec)
as possible, spanning several hours per night. The only requirements are
the weather and your patience! If you need more help on the observing
technique, please feel free to ask on the vsnet-campaign list.
We would sincerely appreciate volunteers who would join the VSNET
Collaboration team to study the wonders of these exotic variable stars.
To join the VSNET campaign collaborative list, send an e-mail to
vsnet-adm@kusastro.kyoto-u.ac.jp (VSNET administrator)
with a line "SUBSCRIBE vsnet-campaign." or your comment to join the
collaboration team.
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