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*** News from VSNET ***
N. J. Brown and M. Yamamoto independently discovered a nova in Sgr.
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 April 28, 2003, as VSNET campaign
circulation 1384
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
Nova Sgr 2003 (RA = 18h40m02s.54, Dec = -33d26'55".1)
According to IAUC No. 8123, N. J. Brown and M. Yamamoto
independently discovered a candidate nova in Sgr. A spectrum taken
by Skuljan showed numerous broad and bright emission lines on a
generally weak continuum. From this description, the object was
confirmed to be a nova (vsnet-campaign-nova 1214, 1215). T. Kato
reported that the location of the nova is almost blank in the 2MASS
survey images. This indicates that the possibility of a giant
secondary is less likely (vsnet-campaign-nova 1217). From reported
pre-discovery images, the nova was still faint in early April and
already bright on April 25 (vsnet-campaign-nova 1218, 1219, 1220,
1221).
SN 2003ds (RA = 10h18m58s.35, Dec = +46d27'15".5)
SN 2003ds is hosted by NGC 3191, a barred-spiral galaxy. NGC 3191
has produced SN Ia 1988B, which was discovered at mag about 15.5,
but it was probably overestimated. The expected maximum for typical
SN Ia is mag about 17 (vsnet-campaign-sn 606).
SN 2003dt (RA = 20h47m17s.56, Dec = +00d18'42".8)
SN 2003dt is hosted by NGC 6962, a spiral galaxy affected some
Galactic extinction. SN Ia 2002ha (maximum mag was about 15.0)
occurred on the same galaxy and still visible at about 15" from SN
2003dt (vsnet-campaign-sn 606).
SN 2003du (RA = 14h34m35s.80, Dec = +59d20'03".8)
SN 2003du is hosted by the UGC 9391, in which the expected maximum
of typical Ia is mag about 13.7. From the reported brightness, it
seems to be a core-collapse event (vsnet-campaign-sn 607, 608). The
spectrum taken by I. Newton telescope on Apr. 24.06 UT revealed that
it was of type Ia about 2 weeks before maximum. The magnitudes
reported to VSNET indicate further brightening to mag 15.3 on
Apr. 24.1 (vsnet-campaign-sn 610). The object is now brightening to
the maximum (vsnet-campaign-sn 611, 612).
POSSIBLE SUPERNOVA IN UGC 9638
(RA = 14h58m04s.92, Dec = +58d52'49".9)
IAUC 8121 informed the discovery of an apparent supernova (mag
16.2) in UGC 9638. It was suspected that the object may be an
USNO-A2.0 star about 3" from this position (vsnet-campaign-sn 609).
RX J1155.4-5641 (RA = 11h55m27s.0, Dec = -56d41'53")
An outburst to 14.4mag was reported by R. Stubbings on April 18
(vsnet-campaign-dn 3594).
WJD004 (RA = 19h01m08s.095, Dec = -21d50'40".38)
D. West reported that WJD004 = GSC 6294:1224 = HD 176454, near
V4743 Sgr, is a variable star. Tycho 1 photometry gives a B-V=0.477
+/- 0.067. SIMBAD lists a spectral type of F6/F7V
(vsnet-campaign-unknown 198).
V551 Sgr (RA = 18h00m56s.46, Dec = -34d35'45".6)
R. Stubbings reported an outburst (14.4mag) of V551 Sgr on April
26 (vsnet-campaign-dn 3595, 3596). The object is apparently fading
rapidly (vsnet-campaign-dn 3598).
(continuous targets)
Betelgeuse (RA = 05h55m10s.3, Dec = +07d24'25")
Betelgeuse has been reported to be extremely faint recently. It
is reported that the star is the *faintest* in the past decade
(vsnet-campaign-mira 56). The fading trend was supported by reports
of observations by M. Koppelman (vsnet-campaign-mira 57) and
S. Otero (vsnet-campaign-mira 58).
V2051 Oph (RA = 17h08m19.1s, Dec = -25d48m31.1s)
On April 21, the "double" profile of eclipses has disappeared, and
the depth again increased to 1.0 mag. The eclipse is highly
asymmetric, with a slower egress than ingress, indicating the
presence of a bright spot (superhump light source) on the disk
(vsnet-campaign-v2051oph 33, 34). On April 22, there were prominent
quasi-period variations (time-scales about 10 min) outside the
eclipses. The eclipse profile on the same night also showed
comparably complex structure to short time-scales. These QPO-like
variation and structured eclipse feature may be associated
(vsnet-campaign-v2051oph 35). T. Kato reported a superhump period
of 0.06414 d using combined data sets (vsnet-campaign-v2051oph 36).
After April 25, the profile, especially that of superhumps, strongly
varied. The light curve showed late superhumps, which have 0.5
phase different from the ordinary superhumps
(vsnet-campaign-v2051oph 40, 41). The object initially faded
gradually, like a superoutburst plateau, but started rapid fading on
April 25-26 (vsnet-campaign-v2051oph 37, 38, 39, 42).
IGR J17091-3624 (RA = 17h09m02s.3, Dec = -36d23'33")
ATEL #152 reported a possible radio counterpart was detected at
the above position. The object is 80" distant from the INTEGRAL
position, but is reported to be the only radio source within the
error (vsnet-campaign-xray 237).
delta Sco (RA = 16h00m19s.9, Dec = -22d37'17")
The object is now reported to be very bright (1.64mag by S. Otero)
again (vsnet-campaign-be 229, 230).
V348 Sgr (RA = 18h40m19s.94, Dec = -22d54'29".1)
The object is now recovering from a deep minimum
(vsnet-campaign-rcb 126).
R CrB (RA = 15h48m34s.40, Dec = +28d09'23".7)
The object is now brightening (vsnet-campaign-rcb 127).
IGR J18539+0727 (RA = 18h53m.9, Dec = +07d27m)
No optical and infrared counterpart has been detected, although
searches of them were performed (vsnet-campaign-xray 230, 231, 232,
233, 234, 235, 236).
GZ Cnc (RA = 09h15m51s.70, Dec = +09d00'50".2)
An outburst to 14.0mag was reported on April 27 by R. Stubbings
(vsnet-campaign-dn 3599).
XTE J1550-564 (RA= 15h50m58s.68, Dec = -56d28'34".8)
B. Monard's observations show that the object is fading. The
fading rate may be slightly larger than those of typical black hole
X-ray transients (vsnet-campaign-xray 238).
Z UMi (RA = 15h02m01s.35, Dec = +83d03'48".7)
The object is further recovering from a faint state
(vsnet-campaign-rcb 128).
V4742 Sgr (RA = 18h02m21s.864, Dec = -25d20'32".22)
D. West reported the nova is showing a decrease in V-Rc
(vsnet-campaign-nova 1213).
BL Lac (RA = 22h02m42.86s, Dec = +42d16'37.6")
BL Lac is reported to be slightly getting active
(vsnet-campaign-blazar 300).
BR Lup (RA = 15h35m51s.61, Dec = -40d34'25".4)
An outburst to about 15mag was reported on April 26 by
R. Stubbings. It may be a post-superoutburst rebrightening
(vsnet-campaign-dn 3597).
*** Future schedule ***
GRB Mini-Symposium in JENAM2003
For more information, http://vsnet.konkoly.hu/jenam03/
[vsnet-campaign-grb 31]
IAU JD17 "ATOMIC DATA FOR X-RAY ASTRONOMY"
ON JULY 22-23, 2003 at the XXVth IAU GENERAL ASSEMBLY
SYDNEY, AUSTRALIA, JULY 13-26, 2003
for more information:
http://vsnet.astronomy.ohio-state.edu/~pradhan/Iau/iau.html
[vsnet-campaign-xray 227]
"X-ray and Radio Emission of Young Stars"
July 28 - 29, 2003, Rikkyo University, Tokyo, Japan
for more information , please contact to kitamoto@rikkyo.ne.jp
[vsnet-campaign-xray 218]
Conference: THE INTERPLAY AMONG BLACK HOLES, STARS AND ISM IN
GALACTIC NUCLEI
in Gramado, south of Brasil, March 1-5, 2004
for more information, please contact to BHSIGN@if.ufrgs.br
[vsnet-campaign-agn 3]
eta Car: The next "shell event"/X-ray eclipse
M. Corcoran reported the event will occur this summer.
Coordinated ground-based observations of eta car along with the
X-ray observations would be really important.
For more information:
Latest X-ray light curve:
http://lheawww.gsfc.nasa.gov/users/corcoran/eta_car/etacar_rxte_lightcurve/
[vsnet-campaign-sdor 23, 24,
25, 26, 28, 29]
[vsnet-campaign-xray 172]
Light curve provided by S. Otero:
http://ar.geocities.com/varsao/Curva_Eta_Carinae.htm
[vsnet-campaign-sdor 22]
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]
*** General information ***
IGR J18539+0727
Image of the field by A. Oksanen:
http://nyrola.jklsirius.fi/ccd/2003/data0421/
[vsnet-campaign-xray 230]
V838 Mon
VRcIc photometry by S. Kiyota, see [vsnet-campaign-v838mon 422, 423]
Nova Sgr 2003
Chart provided by D. West:
http://members.aol.com/dwest61506/page70.html
[vsnet-campaign-nova 1214]
Chart provided by S. Otero:
http://ar.geocities.com/varsao/Carta_V4745_Sgr.htm
[vsnet-campaign-nova 1216]
(This summary can be cited.)
Regards,
Makoto Uemura
Return to the Powerful Daisaku
vsnet-adm@kusastro.kyoto-u.ac.jp
