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[vsnet-campaign-news 189] News from VSNET
*** News from VSNET ***
Short-period fluctuations have been detected in BZ UMa and GZ Cnc.
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 December 30, 2002, as VSNET campaign
circulation 1356
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
V1208 Tau (RA = 04h59m44s.00, Dec = +19d26'23".7)
An outburst (15.0mag) was reported by R. Stubbings on December
26, and it was promptly confirmed by R. Ishioka (vsnet-campaign-dn
3195, 3196). R. Ishioka reported a detection of superhumps with an
amplitude of 0.3mag (vsnet-campaign-dn 3199, 3200). Using a
combined light curves taken by R. Ishioka and K. Tanabe up to
Dec. 28, T. Kato reported a superhump period of 0.07068(4) d. This
value is in good agreement with the 2000 observation
(vsnet-campaign-dn 3212, 3213). The superoutburst is now ongoing
(vsnet-campaign-dn 3204).
GZ Cnc (RA = 09h15m51s.70, Dec = +09d00'50".2)
An outburst (13.5mag) was reported by R. Stubbings on December
26. GZ Cnc is known to be a short period object, which is a good
candidate for an SU UMa star. No superhumps have however been
detected during the past long outburst. So it may be an unusual
object (vsnet-campaign-dn 3197). A rapid fading from the outburst
was reported on December 27 (vsnet-campaign-dn 3208). The Okayama
team performed time-series observation on December 27. The most
noteworthy feature is the presence of high-amplitude quasi-coherent
oscillations (0.1-0.3 mag), which have a typical recurrent time of
20-30 min. The amplitudes of the oscillations seem to have
increased during the observation, and the longer wave became more
prominent. The light curve is totally unlike those taken during the
2000 outburst (Kato et al. 2001, IBVS 5123) (vsnet-campaign-dn
3211).
SN 2002jz (RA = 04h13m12s.52, Dec = +13d25'07".3)
CBET 2 informed the discovery of an apparent supernova in UGC
2984. It was at mag 15.9 on Dec. 23.27, and was below 19.5 on
Dec. 5. It is located about 1" west and 4" south of the center of
UGC 2984, an irregular galaxy. It is superimposed on the bright
central region. UGC 2984 is affected by the Galactic extinction;
Schlegel et al. (1998) suggested that A_B = 2.430 mag, while
Burstein and Heiles (1982) gave a smaller value (A_B = 0.960 mag).
If we take the former, the expected maximum for a typical SN Ia
without the extinction in the host galaxy is mag about 15.0
(vsnet-campaign-sn 522). The spectrum taken with the Las Campanas
Observatory Dupont 2.5-m telescope on Dec. 27.22 revealed that this
supernova, SN 2002jz, was type Ic SN about 10 days past maximum
(vsnet-campaign-sn 523).
SDSSp J173008.38+624754.7 (RA = 17h30m08s.38, Dec = +62d47'54".7)
An outburst (14.7mag) was reported by T. Kinnunen on December 23.
A fading to 15.3: mag was reported on December 24. It may be a
normal outburst (vsnet-campaign-dn 3191).
RX J0558.3+6735 (RA = 05h58m18s.0, Dec = +67d53'45")
An outburst (14.2mag) was reported by T. Kinnunen on December 23
(vsnet-campaign-dn 3192).
PY Per (RA = 02h50m00s.14, Dec = +37d39'23".1)
An outburst was detected on December 26, and it is now ongoing
(vsnet-campaign-dn 3210).
(continuous targets)
IY UMa (RA = 10h43m56s.87, Dec = +58d07'32".5)
A. Oksanen reported that they detected three eclipses with a
smoothly fading trend on December 22. All three eclipses were about
2 minutes ahead of the predicted time (vsnet-campaign-dn 3179). The
object then faded quickly. It was a normal outburst
(vsnet-campaign-dn 3182).
SN 2002jy (RA = 01h21m16s.27, Dec = +40d29'55".3)
The CfA team revealed that it was type Ia SN near maximum on
Dec. 26.11 (vsnet-campaign-sn 523).
BZ UMa (RA = 08h53m44s.3, Dec = +57d48'40".1)
The object was rapidly fading from the outburst on December 22.
Superimposed on this fading, the Okayama team detected modulations
with a period close to 0.066 d. This period looks like to be
associated with the orbital period. Short-period quasi-periodic
oscillations with variable amplitudes were also observed. The
strongest period was around 0.023 d. The overall light curve on
Dec. 22 generally resembles that of HT Cam, despite the lack of an
acceleration of the fading rate during the latest stage
(vsnet-campaign-dn 3184). On Dec. 23 and 24, the object showed
large-amplitude (up to 0.8 mag) variations. At least some of the
major peaks seem to have a periodicity close to the orbital period.
Other shorter period oscillations were also present
(vsnet-campaign-dn 3194). On Dec. 25, strong and highly coherent
variations still appeared. T. Kato reported that the
best-determined period is 0.0657(7) d, which is slightly shorter
than the orbital period (vsnet-campaign-dn 3209).
RX J1155.4-5641 (RA = 11h55m27s.0, Dec = -56d41'53")
The superoutburst continued until December 26 when R. Stubbings
reported a rapid fading to 13.6mag (vsnet-campaign-dn 3187, 3198).
It further faded on December 27 (vsnet-campaign-dn 3205).
V383 Vel (RA = 10h21m41s.7, Dec = -49d49'24".33)
The outburst still continued on December 24. The duration may be
long for SS Cyg type outburst (vsnet-campaign-dn 3185). The long
outburst is now ongoing (vsnet-campaign-dn 3206).
BU Tau (RA = 03h49m11s.19, Dec = +24d08'12".4)
P. Harmanec commented that for at least three years BU Tau is in
its undisturbed state with V=5.04 mag. The current brightness
corresponds roughly to the true brightness of the central star,
unaffected by a contribution from an envelope (vsnet-campaign-be
205). On the other hand, D. West reported his observation of
V=4.91+/-0.02 on December 22, which indicates that it is getting
brighter (vsnet-campaign-be 206).
CU Vel (RA = 08h58m32s.87, Dec = -41d47'50".8)
The superoutburst has entered a rapid fading phase, as indicated
by the observation by R. Stubbings on December 24
(vsnet-campaign-dn 3183, 3186). After the rapid fading, the light
curve on December 26 by P. Nelson showed double-wave modulations,
which are likely related to late superhumps (vsnet-campaign-dn
3201).
V844 Her (RA = 16h25m01s.69, Dec = +39d09'25".9)
The object has been in superoutburst since December 21
(vsnet-campaign-dn 3181, 3190).
RR Tau (RA = 05h39m30s.53, Dec = +26d22'26".3)
A rapid, deep fading to 13.7was reported by E. Muyllaert on
December 25 (vsnet-campaign-orion 38).
U Gem (RA = 07h55m05s.55, Dec = +22d00'09".2)
The outburst continues (vsnet-campaign-dn 3188, 3207).
eta Gem (RA = 06h14m52s.87, Dec = +22d30'24".5)
It is still in the possible eclipse (vsnet-campaign-ecl 54, 55).
BL Lac (RA = 22h02m42s.86, Dec = +42d16'37".6)
The active state continues (vsnet-campaign-blazar 292).
TU Men (RA = 04h41m38s.10, Dec = -76d36'09".7)
In the light curve taken by T. Richards on December 21, superhumps
were not yet prominent, while the duration of the outburst indicated
a superoutburst (vsnet-campaign-dn 3180). The outburst continues
until December 25, when a rapid fading to 13.0mag was reported by
R. Stubbings (vsnet-campaign-dn 3189, 3193).
MisV1147 (RA = 22h54m03s.78, Dec = +58d54'02".1)
T. Kato reported that the object was in a faint state on December
23, which may be inconsistent with the proposed quasi-periodic
fadings. The fadings may be obscuration events
(vsnet-campaign-unknown 165, 166, 167). The object had recovered on
December 25 (vsnet-campaign-unknown 168).
*** Future schedule ***
The 2003 Gamma Ray Burst conference
Hosted by Los Alamos,
in Santa Fe, New Mexico (USA), between September 8 and 12, 2003
http://grb2003.lanl.gov/
[vsnet-campaign-grb 13]
WEBT campaign on Mkn 421
M. Villata announced possible WEBT campaign on Mkn 421, in
December 2002 and February-March 2003, to be carried out during
multifrequency campaigns.
The relevant information on the MW campaign of December 2-16 is at
the VERITAS site <http://veritas.sao.arizona.edu> .
[vsnet-campaign-blazar 287]
[vsnet-campaign-blazar 288]
SUPERNOVAE (10 YEARS OF SN1993J)
22-26 April 2003, Valencia, Spain
Web site: http://vsnet.uv.es/2003supernovae/
[vsnet-campaign-sn 342]
[vsnet-campaign-sn 452]
[vsnet-campaign-sn 512]
*** General information ***
V1208 Tau
Chart and Sequence presented by M. Simonsen:
http://joevp.20m.com/charts/henden/Her%20to%20Vul/
[vsnet-campaign-dn 3202]
GZ Cnc
Chart and Sequence presented by M. Simonsen:
http://joevp.20m.com/charts/henden/And%20to%20Gem/
[vsnet-campaign-dn 3203]
BZ UMa
Hump profile:
http://vsnet.kusastro.kyoto-u.ac.jp/pub/vsnet/DNe/BZ_UMa/bzph1.gif
[vsnet-campaign-dn 3209]
(This summary can be cited.)
Regards,
Makoto Uemura
Return to Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
VSNET Home Page