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[vsnet-campaign-news 166] News from VSNET
*** News from VSNET ***
DH Aql and V2276 Sgr now experience relatively rare outbursts.
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 August 5, 2002, as VSNET campaign circulation 1330
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
V2276 Sgr (RA = 20h26m22s.16, Dec = -43d40'31".9)
R. Stubbings reported on August 4 that the dwarf nova
V2276 Sgr is undergoing an outburst (14.8mag). The last
reported outburst dates back to 1998, suggesting a low
frequency of outbursts. Judging from the outburst amplitude,
the object may be a short-period system such as an SU UMa-type
star. Close time-series CCD observations are very strongly
encouraged (vsnet-campaign-dn 2696).
DH Aql (RA = 19h26m12s.05, Dec = -10d15'21".4)
As detected by R. Stubbings on July 27, the SU UMa-type dwarf
nova, DH Aql is now in outburst (12.6mag). The Kyoto team
confirmed this outburst at Rc=12.56 on July 27 13:30 (UT). The last
superoutburst was reported on 2000 July 31 (vsnet-campaign-dn 2661).
A partial analysis of the July 27 data by the Kyoto team has shown
the presence of humps with an amplitude of 0.1 mag. T. Kato
reported that these humps seem to be superhumps at the growing
stage (vsnet-campaign-dn 2667). R. Santallo reported a detection
of clear superhumps (amplitude 0.11mag) on July 28 (vsnet-campaign-dn
2668, 2671). The light curves after July 29 show fully-grown
superhumps (vsnet-campaign-dn 2677, 2678, 2685, 2689, 2693).
M. Uemura reported that the data sets obtained by the VSNET
collaboration team show a superhump period of 0.080029 +/- 0.000008 d.
He also noticed that the data shows a gradual decreasing of
superhump period during July 29 - August 1 (vsnet-campaign-dn 2699).
The superoutburst still continues (vsnet-campaign-dn 2662, 2674,
2676, 2670, 2681, 2687, 2694, 2698).
SN 2002ed (RA = 14h06m38s.2, Dec = -05d27'29")
SN 2002ed was discovered by B. Monard on July 27.77 UT when
it was mag about 16.5. The position is 55" east and 15" south
of the center of a face-on spiral galaxy NGC 5468. It was also
detected on the KAIT images taken on July 24-29, but was not
seen on July 23 image (limiting mag 17.5) taken by Berto.
SN 2002cr was discovered this May in the same galaxy. It was of
type Ia, and reached its maximum (mag about 14.2) around May 13.
It can still be seen at mag about 17.8, so you can enjoy "double
explosion" for a while. NGC 5468 also produced SN Ia 1999cp.
NGC 5468 is open spiral galaxies, which is active in star formation
(vsnet-campaign-sn 453). SN 2002ed turned out to be a type II SN
(the ANU group, IAUC 7947) (vsnet-campaign-sn 458).
V767 Cen (RA = 13h53m57s.07, Dec = -47d07'41".1)
A possible outburst to 6.0mag was reported, but it seems to
be just a part of large amplitude short-term variations which
have already been known (vsnet-campaign-be 196, 197).
UZ Ser (RA = 18h11m24s.90, Dec = -14d55'33".9)
Based on recent observations, UZ Ser was suggested to have
entered a standstill (vsnet-campaign-dn 2660). However, a fading
under 14.5mag was observed on July 27 (vsnet-campaign-dn 2665).
RZ Psc (RA = 01h09m40s.07, Dec = +27d57'28".0)
P. Schmeer reported that RZ Psc is still faint at 12.6-12.7mag.
This is the longest fading ever reported to VSNET
(vsnet-campaign-orion 34).
V3774 Sgr (RA = 18h41m41s.34, Dec = -32d54'35".7)
H. Yamaoka examined many DSS images of V3774 Sgr and reported
that the position in the GCVS and Downes' online catalog is rather
good, but their minimum magnitude (<19.0p mag) seems to be
underestimated. Based on DSS images, the quiescent magnitude is
proposed to be around 17.5-18.0 (vsnet-campaign-dn 2692).
GRB 020801 (RA = 20h59m09s, Dec = -51d55'25")
P. Cacella reported a curious object in the field reported
in HETE 2177/28 (http://intermega.globo.com/cacella/GRB.htm;
vsnet-campaign-sn 456, vsnet-campaign-grb 2). B. Monard
reported no bright object over 19.0mag was detected in images
taken on August 2 (vsnet-campaign-grb 3).
SN 2002ef (RA = 23h51m29s.54, Dec = -13d22'46".4)
SN 2002ef was discovered by the KAIT team on images taken on
July 30 (16.5mag) and 31 (16.2mag). NGC 7761, the host galaxy
of SN 2002ef, is a lenticular galaxy, which would produce only
SNe Ia. The discovery magnitude is nearly the same as the
expected maximum for a typical SN Ia (vsnet-campaign-sn 455).
According to IAUC 7945, the CfA team revealed that SN 2002ef
is of type Ia, near maximum on Aug 1.43 (vsnet-campaign-sn 457).
SN 2002eg (RA = 19h49m47s.25, Dec = +50d41'53".6)
SN 2002eg was discovered by E. Sanders and the KAIT team.
The host galaxy of SN 2002eg, UGC 11486, produced SN II 2002dv
on this July. The discovery image of SN 2002eg can be found at:
http://vsnet.geocities.com/ellasanders/SN_02eg.html , on which SN
2002dv is marginally and SN 2002eg is clearly seen. The expected
maximum for typical SN Ia is mag about 17.3 (vsnet-campaign-sn 455).
SN 2002eh (RA = 02h26m08s.45, Dec = +31d54'45".2)
SN 2002eh appeared in the spiral galaxy NGC 917. The expected
maximum for typical SN Ia is mag about 16.1 (vsnet-campaign-sn 459).
(continuous targets)
V729 Sgr (RA = 19h16m49s.15, Dec = -26d14'33".2)
R. Stubbings reported that V729 Sgr experienced an outburst
(13.2mag) on July 26 (vsnet-campaign-dn 2659). The object
was reported to start fading on August 1 (vsnet-campaign-dn
2666, 2673, 2691).
IY UMa (RA = 10h43m56s.87, Dec = +58d07'32".5)
A possible outburst was reported on July 28, but no major
outburst has been confirmed (vsnet-campaign-dn 2680).
BF Ara (RA = 17h38m10s.40, Dec = -47d10'43".4)
An outburst (14.4mag) was reported by R. Stubbings on July 30
(vsnet-campaign-dn 2679, 2688). A fading was observed on August 1
(vsnet-campaign-dn 2690).
TU Crt (RA = 11h03m36s.50, Dec = -21d37'45".6)
The object entered a rapid fading phase from superoutburst
on July 30 (vsnet-campaign-dn 2663, 2675, 2684).
V348 Sgr (RA = 18h40m19s.94, Dec = -22d54'29".1)
The bright state continues at about 13.0mag (vsnet-campaign-rcb
50, 52, 54).
omicron Cet (RA = 02h19m20s.67, Dec = -02d58'27".1)
The object is near maximum (vsnet-campaign-mira 28, 29, 30).
PU Vul (RA = 20h21m13s.30, Dec = +21d34'18".0)
The gradual fading seems to continue (vsnet-campaign-symbio 24).
V503 Cyg (RA = 20h27m15s.61, Dec = +43d41'45".5)
T. Kato noticed that the interval of the recent two successive
superoutbursts breaks the shortest record of SU UMa stars except
ER UMa stars (vsnet-campaign-dn 2657, 2658, 2664). J. Pietz
reported a sequence of 0.1 mag humps and substructures on July 28
(vsnet-campaign-dn 2669, 2672). The object has faded from the
superoutburst (vsnet-campaign-dn 2682, 2695, 2697).
V4641 Sgr (RA = 18h19m21s.6, Dec = -25d24'25")
The light curve obtained by K. Torii on July 20 shows that
V4641 Sgr was rather inactive (vsnet-campaign-v4641sgr 157).
On July 24, 26, and 29, M. Linnolt reported no dramatic activity was
observed during his visual monitoring (vsnet-campaign-v4641sgr 158,
160, 161). Possible new activities were reported on July 29
based on some visual observations (vsnet-campaign-v4641sgr 162).
The object seems to be calm state now (vsnet-campaign-v4641sgr 159).
DY Per (RA = 02h35m17s.12, Dec = +56d08'44".7)
The object is brightening from a minimum (vsnet-campaign-rcb 51).
V803 Cen (RA = 13h23m44.5s, Dec = -41d44'30".1)
R. Stubbings detected an outburst (13.9mag) on July 31
(vsnet-campaign-dn 2686).
V2540 Oph (RA = 17h37m34s.36, Dec = -16d23'18".4)
A. Retter reported that they detected periodic modulations
with the best period of ~2.4 h. He proposed that this period
could be the binary orbital period. It would be then in the
period gap of cataclysmic variables. He further reported that
the nova would be an intermediate polar supporting the possible
connection between the transition phase in novae and intermediate
polars if other periods are confirmed. T. Kato commented that
the transition phase oscillations of novae now seem to be better
understood as a natural consequence of an instability in the
super-Eddington winds (vsnet-campaign-nova 943, 944, 946, 947,
948, 949, 950, 952, 953, 954, 957, 958, 959, 960, 961, 962).
D. West performed time-series photometry on July 31 and reported
no periodic modulations were detected (vsnet-campaign-nova 945).
His observations on August 1 show 0.031, 0.043, and 0.07 day
periodicities (vsnet-campaign-nova 955, 951).
CH Cyg (RA = 19h24m33s.07, Dec = +50d14'29".5)
Recently reported observations indicate that the object is
relatively brighter (vsnet-campaign-symbio 23).
SN 2002ec (RA = 15h19m24s.89, Dec = +20d53'14".0)
The Australian National Univ. (ANU) group has revealed that
it is of type Ia near maximum on July 31.43 (IAUC 7946)
(vsnet-campaign-sn 458).
*** Future schedule ***
International Workshop
HIGH RESOLUTION X-RAY SPECTROSCOPY with XMM-NEWTON and CHANDRA
24th and 25th October 2002
For more details, visit the workshop website:
http://vsnet.mssl.ucl.ac.uk/~gbr/rgs_workshop/
[vsnet-campaign-xray 152]
===== International Symposium ======
"The Universe Viewed in Gamma-rays
--- Univ. Tokyo Workshop 2002 ---"
September 25-28, 2002, Kashiwa, Chiba, Japan
http://icrhp9.icrr.u-tokyo.ac.jp/Symp2002.html
[vsnet-campaign-blazar 265]
International Symposium: The Universe viewed in gamma-rays
--- Univ. Tokyo Workshop 2002 ---
September 25-28, 2002, Kashiwa, Chiba, Japan
http://icrhp9.icrr.u-tokyo.ac.jp/Symp2002.html
[vsnet-campaign-blazar 264]
Texas in Tuscany
XXI Symposium on Relativistic Astrophysics
Florence, Italy, December 9-13, 2002
For more information:
http://vsnet.arcetri.astro.it/~texaflor/
[vsnet-campaign-xray 142]
NEW X-RAY RESULTS FROM CLUSTERS OF GALAXIES AND BLACK HOLES
34th COSPAR Scientific Assembly
10th to 12th October 2002 - Houston, Texas
For more information, visit the session website:
www.mssl.ucl.ac.uk/www_astro/cospar
[vsnet-campaign-xray 124]
[vsnet-campaign-agn 2]
[vsnet-campaign-xray 133]
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]
34TH COSPAR - GRB AFTERGLOW PHYSICS
HOUSTON, TX, USA, 10-19 OCTOBER 2002
Main Scientific Organizer (MSO):
Elena Pian - INAF, Astronomical Observatory of Trieste, Italy -
pian@ts.astro.it
http://vsnet.ts.astro.it/topics/topix.html
[vsnet-campaign-grb 1]
*** General information ***
V4740 Sgr
Time-series photometry by T. Richards, see [vsnet-campaign-data 99]
gamma Cas
1991, 1996, and 2002 data obtained by P. Ferenc,
see [vsnet-campaign-be 195]
V729 Sgr
Eclipse ephemeris, see [vsnet-campaign-dn 2659, 2683]
DH Aql
Time-series observations by T. Richards, see [vsnet-campaign-data 100, 101]
SN 2002ed
H. Yamaoka performed astrometry using B. Monard's image,
see [vsnet-campaign-sn 454]
The discovery image can be seen at:
http://vsnet.kusastro.kyoto-u.ac.jp/pub/vsnet/SNe/sn2002ed/
[vsnet-campaign-sn 453]
V2540 Oph
Spectrum by C. Buil:
http://astrosurf.com/buil/us/noph/noph.htm
[vsnet-campaign-nova 956]
delta Sco
Spectrum by D. West:
http://hometown.aol.com/dwest61506/index.html
[vsnet-campaign-be 198]
(This summary can be cited.)
Regards,
Makoto Uemura
Return to Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
VSNET Home Page