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[vsnet-campaign-news 69] AstroAlert: AL Com superhumps finally!
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AL Comae Berenices: superhumps finally!
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From [vsnet-campaign 950]:
The VSNET AL Com page has been updated.
The light curve shows data sets kindly sent by P. Sobotka, R. Novak,
G. W. Billings, B. Martin, K. Hornich, J. Pietz, and G. Masi,
and also includes Kyoto observations.
We show the average hump profile on May 28 when normal superhumps are
reported to be growing.
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/DNe/alcom0105.html
Regards,
Makoto Uemura
From [vsnet-campaign-dn 855]:
We have received a data set from G. W. Billings on May 27. The data
and Kyoto data on May 28 show humps with an amplitude of ~0.4 mag.
The amplitude is obviously larger than that of early superhumps.
We perform PDM anarysis on the combined data and obtaind a period of
0.0581d, which is 2.6% longer than the orbital period of 0.0566d.
The folded light curve by this period shows a single-peaked profile.
Finaly, the usual superhumps are growing.
A sudden dip were observed during the last outburst of AL Com in 1995.
Continuous observations are encouraged.
Regards,
Ryoko Ishioka
VSNET Collaboration team
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Recent observations:
YYYYMMDD(UT) mag observer
20010524.880 136 (M. Verdenet)
20010524.887 131 (J. Ripero)
20010524.901 133 (P. A. Dubovsky)
20010524.908 134 (M. Reszelski)
20010524.931 132 (R. J. Bouma)
20010524.940 134 (H. McGee)
20010525.406 130 (R. Stubbings)
20010525.423 132: (P. Nelson)
20010525.875 136 (Wolfgang Kriebel)
20010525.880 137 (M. Verdenet)
20010525.890 131 (J. Ripero)
20010525.908 134 (P. A. Dubovsky)
20010525.919 135 (M. Verdenet)
20010525.940 133 (R. J. Bouma)
20010525.949 136 (M. Reszelski)
20010525.980 139 (F. Pujol)
20010526.147 135 (R. J. Modic)
20010526.558 133 (A. Pearce)
20010526.837 136CR (G. Masi)
20010526.881 134 (J. Ripero)
20010526.990 139 (F. Pujol)
20010527.558 134 (A. Pearce)
20010527.890 138 (M. Verdenet)
20010527.901 137 (E. Muyllaert)
20010527.919 137 (M. Verdenet)
20010528.547 134 (A. Pearce)
20010528.887 134 (J. Ripero)
20010528.890 137 (M. Verdenet)
20010528.923 136 (G. Poyner)
20010528.930 137 (M. Verdenet)
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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