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[vsnet-campaign-news 89] AstroAlert: V818 Sco (Sco X-1) extremely active
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The X-Ray Binary Sco X-1 (V818 Sco) is Extremely Active
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Sco X-1 (V818 Sco) is the brightest (persistent) low-mass X-ray binary
in the sky. The object is a close binary containing a neutron star,
which accretes matter from the companion star, and emits X-rays.
Low-mass X-ray binaries are often very faint in the visual light, and
Sco X-1 (V818 Sco) is a rare example which amateur telescope can easily
reach.
Berto Monard (South Africa) and Peter Nelson (Australia) report that
the object, usually at around mag 12.7, has brightening significantly,
and looks to be still brightening.
Observers are strongly encourage to observe this "monster" in the
northern Scorpius.
V818 Sco is located at 16h 19m 55s.0 -15o 38' 24" (J2000.0).
Recent observations reported to VSNET:
YYYYMMDD(UT) mag observer
20010510.758 127 (B. Monard)
20010511.767 127 (B. Monard)
20010512.788 127 (B. Monard)
20010513.816 126 (B. Monard)
20010514.772 127 (B. Monard)
20010515.774 127 (B. Monard)
20010517.767 127 (B. Monard)
20010518.794 127 (B. Monard)
20010519.769 127 (B. Monard)
20010520.753 128 (B. Monard)
20010521.738 128 (B. Monard)
20010523.783 127 (B. Monard)
20010525.769 129 (B. Monard)
20010526.732 128 (B. Monard)
20010527.756 126 (B. Monard)
20010529.791 127 (B. Monard)
20010530.951 122 (B. Monard)
20010608.732 127 (B. Monard)
20010609.740 135 (B. Monard)
20010610.728 126 (B. Monard)
20010612.766 127 (B. Monard)
20010613.785 130 (B. Monard)
20010615.737 128 (B. Monard)
20010616.764 127 (B. Monard)
20010618.756 128 (B. Monard)
20010619.716 128 (B. Monard)
20010620.688 128 (B. Monard)
20010621.725 134 (B. Monard)
20010622.760 134 (B. Monard)
20010623.741 133 (B. Monard)
20010625.694 134 (B. Monard)
20010628.006 127 (B. Monard)
20010628.722 127 (B. Monard)
20010630.694 127 (B. Monard)
20010703.467 <114 (P. Nelson)
20010704.419 120: (P. Nelson)
20010708.739 123 (B. Monard)
20010711.812 120 (B. Monard)
20010712.544 116 (P. Nelson)
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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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