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[vsnet-campaign-news 56] News from VSNET 53
*** News from VSNET ***
Another Wolf-Rayet star WR106 turned out to be a large amplitude
variable star, like the "pinwheel star" WR104. They may imply a new
group of variable stars.
For more detail information about these objects,
see below, "VSNET Weekly Campaign Summary" of the last week.
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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.
The "News from VSNET", mainly focusing on recent remarkable activities of
CVs and related systems, is issued on a weekly basis, except on occasions
of extremely urgent or transient events.
Please refer to the VSNET Home Page for more details of events and
objects listed.
VSNET Home Page: http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/
VSNET provides a number of mailing lists, on which various news and topics
are discussed. Subscriptions to the VSNET mailing lists are free of charge;
please refer to the instruction on the above page if a reader needs more
information of the list structure.
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."
(VSNET campaign members are strongly recommended to subscribe to vsnet-alert
at the same time).
Regards,
Taichi Kato
On behalf of the VSNET administrator team
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The following was issued on May. 7, 2001, as VSNET campaign circulation 896.
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
WR106 = HadV84 (RA = 18h04m43s.5, Dec = -21d09'29")
K. Haseda reported the discovery of a new variable star (HadV84).
The object is identified with a dusty WC9 star, WR 106, which is
similar to WR 104 = HadV82, the "pinwheel star". These observations
may suggest a new class of WR-type variable stars. Since the light
variation may suggest that WR 106 = HadV84 is a twin od WR 104 =
HadV82, a vigorous search for binarity, and the evidence of the
"chimney mechanism" proposed for WR 104 is strongly encouraged.
Infrared interferometric observations as in WR 104 would be helpful
in elucidating the peculiar characteristics (vsnet-campaign-be 116,
vsnet-campaign 892, vsnet-campaign-news 55). The full range of
variability is reported to be 11.7-14.1p (vsnet-campaign-be 117).
BZ UMa (RA = 08h53m44s.3, Dec = +57d48'40".1)
The SU UMa-candidate BZ UMa experienced a relatively rare outburst,
as reported by Pavol A. Dubovsky (vsnet-outburst 2126) at mv=10.8
on May 1.8681 and by M. Reszelski (vsnet-alert 5857) at mv=10.8 on
May 1.891. The last outburst occurred in 2000 May (normal outburst).
None of previously observed outbursts of BZ UMa showed clear
characteristics of a superoutburst, which is atypical for a dwarf
nova below the period gap (vsnet-campaign 893). R. Novak performed
time-series photometry on May 4 and reported no clear superhumps
were seen (vsnet-campaign-dn 746, 747). The outburst continued
until May 3 and started rapid fading (vsnet-campaign-dn 731, 735,
743, 748, 749, 753, vsnet-campaign 895). The outburst is also
a normal one.
BR Lup (RA = 15h35m51s.61, Dec = -40d34'25".4)
As reported by R. Stubbings on April 28, the SU UMa-type dwarf
nova BR Lup is undergoing a superoutburst. The object attained
the peak brightness at 13.7mag on April 30. The last likely
superoutburst was observed in 2000 December (vsnet-campaign 891).
The superoutburst is now ongoing and the current magnitude is
about 14.0mag (vsnet-campaign-dn 733, 737, 752).
SN 2001bf (RA = 18h01m33s.99, Dec = +26d15'02".3)
IAUC 7620 reports that the discovery of SN 2001bf was made by
M. Armstrong on May 3.02 at mag 16.5, and he confirmed it on May
4.965 at mag 15.9. The reported position is 5" east and 8" south
of the center of the spiral (?) galaxy MCG +04-42-22. From the
recession velocity of the host galaxy (4647 km/s from NED),
the expected maximum of the typical SN Ia would be around 15.9 mag
(vsnet-campaign-sn 176).
V344 Pav (RA = 19h16m10.21s, Dec = -62d35'54".4)
An outburst (14.8mag) of V344 Pav was reported on April 29
by R. Stubbings. The object further brightened on April 30,
which indicates the outburst was a possible superoutburst
(vsnet-campaign-dn 725). The object is still in the outburst.
The magnitude is about 14.9mag or fainter (vsnet-campaign-dn 732, 750).
SS UMi (RA = 15h51m22s.4, Dec = +71d45'11".1)
An outburst was detected on April 28 by M. Reszelski at 15.5mag,
and then, the object further brightened to 14.8mag on May 2.
This is atypical for a normal outburst. The present epoch may be
a little early for a superoutburst, but one may be ongoing
(vsnet-campaign-dn 734).
NSV08383 (RA = 17h16m53s, Dec = -65d32'42")
An outburst of 14.2mag was reported on May 2 by A. Pearce.
The last outburst was in 2000 September (vsnet-campaign-dn 745).
(continuous targets)
QW Ser (RA = 15h26m13s.99, Dec = +08d18'03".8)
R. Novak performed time-series CCD observation on April 30 and
confirmed the outburst (vsnet-campaign-dn 729). His 3 hours light
curve shows only linear fading modulated by some flickering
(vsnet-campaign-dn 741). On May 1, a fading from the outburst was
reported (vsnet-campaign-dn 730), but the fading speed was rather
slow for normal outbursts (vsnet-campaign-dn 726, 738).
DV UMa (RA = 09h46m36s.67, Dec = +44d46'45".1)
R. Novak performed CCD observations April 25 and 26, and reported
the object became faint (vsnet-campaign-dn 729). The normal outburst
was terminated (vsnet-campaign-dn 727).
SN 2001bb (RA = 13h43m25s.31, Dec = -29d48'13".1)
IAUC 7616 informed that the spectra of SN 2001bb have been taken
by Lick and KPNO, which reveal that it is of type I SN, but the
subclass is not yet uncertain. It can be a luminous SN Ia, or
hypernova (vsnet-campaign-sn 173).
V803 Cen (RA = 13h23m44.5s, Dec = -41d44'30".1)
The oscillation is still reported. The object seems to modulate
between 13.4-14.4 mag (vsnet-campaign-dn 739, 751, 758).
3C 279 (RA = 12h56m11s.1, Dec = -05d47'20")
The object still shows the strong activity (vsnet-campaign-blazar 191).
CR Boo (RA = 13h48m55s.42, Dec = +07d57'30".3)
The object start fading from the outburst. The current magnitude
is about 14.2mag or fainter (vsnet-campaign-dn 740).
V445 Pup (RA = 07h37m56s.88, Dec = -25d56'59".1)
Some observations indicate the object is brightening again in
the last week (vsnet-campaign-nova 293, 294).
OJ287 (RA = 08h51m57s, Dec = 20d17'59")
The strong activity around 14.9mag is still reported
(vsnet-campaign-blazar 192).
BZ Cam (RA = 06h29m34s.49, Dec = +71d04'39".5)
The bright state at about 12.2mag still continues (vsnet-campaign-nl 18).
Delta Sco (RA = 16h00m19s.9, Dec = -22d37'17")
The object is still at very bright state (vsnet-campaign-be 118, 121).
T. Gandet reported the provisional spectroscopic period of
78.860 +/- 0.0017 days and the other orbital elements obtained
through the analysis of 56 published radial velocities that cover
the interval 1903-1975 (vsnet-campaign-be 119, 120). S. Otero
discusses in [vsnet-campaign-be 122] about a possibility that the
current variation is due to an eclipse of the ejected ring.
T. Gandet also wrote in [vsnet-campaign-be 123] that delta Sco's
mechanism might be analogue to EN Lac-type and/or Beta CMa-like.
U Gem (RA = 07h55m05s.55, Dec = +22d00'09".2)
The outburst continued for 10 days, and then, has began fading
since around May 6 (vsnet-campaign-dn 728, 736, 757).
MV Lyr (RA = 19h07m15s.93, Dec = +44d01'10".7)
The faint state still continues. The object is fainter than
15.2mag as reported by M. Reszelski (vsnet-campaign-nl 19).
XTE J1118+480 (RA = 11h18m10s.9, Dec = +48d02'12".9)
According to IAU Circular 7617, J. Casares et al. detected
superhumps with a period of 0.17049(1) day using their data
during Dec. 2000 - Apr 2001. The data set obtained during the
outburst in 2000 by VSNET team shows the mean superhump period
during the outburst is slightly longer than that reported in
IAUC 7617, which may imply a continuous period changing. In the
case of SU UMa-type dwarf nova, the "late superhump" is sometimes
observed after superoutburst (vsnet-campaign 894).
IX Dra (RA = 18h12m32s.2, Dec = +67d04'41")
An Observation on May 2 by M. Reszelski indicates the object
experienced another outburst at 14.9mag (vsnet-campaign-dn 744).
The Kyoto team observations on May 3 confirmed this outburst
and a rapid fading on May 4 (vsnet-campaign-dn 754).
SN 2001X (RA = 15h21m55s.46, Dec = +05d03'43".1)
The current magnitude is about 15.3mag (vsnet-campaign-sn 175).
SN 2001ay (RA = 14h26m17s.00, Dec = +26d14'55".8)
The SN is now gradually fading (vsnet-campaign-sn 174).
MKN 421 (RA = 11h04m27s, Dec = +38d12'32")
The object is now at about 12.9mag which is slightly fainter
(vsnet-campaign-blazar 193).
*** Future schedule ***
CR Boo and V803 Cen campaign conducted by J. Patterson
For more information, see [vsnet-campaign-dn 640 and vsnet-campaign 852]
Elizabeth and Frederick White Workshop
AGN variability across the Electromagnetic Spectrum
25 - 29 June 2001 Sydney, Australia
For more information, see [vsnet-campaign-blazar 168].
Two Years of Science with Chandra *
* This meeting will also be the 12th Annual Maryland Astrophysics
Conference
September 5-7, 2001
For more information, see [vsnet-campaign-xray 66]
*** General information ***
U Gem
eclipse ephemeris, see [vsnet-campaign-dn 759]
(This summary can be cited.)
Regards,
Makoto Uemura
vsnet-adm@kusastro.kyoto-u.ac.jp
Return to Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
VSNET Home Page