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[vsnet-campaign-news 79] AstroAlert: AL Com suddenly faded
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AL Comae Berenices suddenly faded
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The observation of the VSNET Collaboration team, Kyoto, shows that
AL Com is rapidly fading from the current rare superoutburst.
Its magnitude is about 16.7 mag on June 11.5 UT.
AL Com was observed at 14.7 on 10.949 June UT by Gary Poyner.
The rapid decline took place between 10.949 and 11.5 UT, 24 dars after
the onset of the current outburst. In the 1995 outburst, another
long-lasting outburst started following the rapid decline, 28 days after
the the onset of the outburst (the phenomenon called as "post-superoutburst
rebrightening"). Detailed observation during in such stages are cruicial
in understanding the mechanism of outbursts in extremely infrequently
outbursting dwarf novae, as in AL Com. Further observations are therefore
very strongly encouraged.
Related URLs on VSNET:
http://vsnet.kusastro.kyoro-u.ac.jp/vsnet/DNe/alcom0105.html (current outburst)
http://vsnet.kusastro.kyoro-u.ac.jp/vsnet/DNe/alcom1.html (1995 outburst)
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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vsnet-adm@kusastro.kyoto-u.ac.jp
Return to Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
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