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*** News from VSNET ***
The SU UMa-type dwarf nova, KS UMa is now in outburst. Its early
evolution of superhumps were revealed.
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 February 24, 2003, as VSNET campaign
circulation 1372
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
KS UMa (RA = 10h20m26s.54, Dec = +53d04'33".5)
As reported by E. Muyllaert and G. Poyner on Feb. 18, the SU
UMa-type dwarf nova, KS UMa is now in outburst (12.7, 12.9mag;
vsnet-campaign-dn 3447). There was no clear modulations in the
light curve obtained by T. Vanmunster on Feb. 18/19
(vsnet-campaign-dn 3449). A subsequent observation by K. Nakajima
showed a weak (~0.05 mag) signal, which may be attributed to
early-stage superhumps (vsnet-campaign-dn 3454). T. Vanmunster then
detected clear superhumps with an amplitude of 0.21 mag on February
19/20 (vsnet-campaign-dn 3455, 3459). Using the combined data,
T. Kato reported that the superhump period of the early
superoutburst phase was 0.07068(7) d, which is substantially longer
than the previously reported periods (vsnet-campaign-dn 3460). On
Feb. 22, T. Kato reported that, although there was a slight tendency
of a period decrease during this period, no striking period change
as recorded in UV Gem was observed (vsnet-campaign-dn 3464).
A. Olech et al., the Ostrowik team, performed time-series
observation on Feb. 21/22 and 22/24 and reported a period of 0.0699
+/- 0.0002 days (vsnet-campaign-dn 3465, 3476). T. Kato revised the
superhump period to be 0.07026(2) d on Feb. 23. The rate of period
change dot(P)/P was around -3*10(^4). While the baseline was still
short, if confirmed, this negative period derivative is one of the
most pronounced among moderate-period SU UMa-type dwarf novae
(vsnet-campaign-dn 3467). In the late Feb. 23 - early Feb. 24 data,
the main superhump maxima became weaker, while other peaks became
stronger. The profile then become very complex, which resembles
that of superhumps during the rapid decline stage. However, the
present stage is too early for such a rapid decline, neither
observations show such a rapid trend (vsnet-campaign-dn 3484).
The superoutburst is now ongoing (vsnet-campaign-dn 3448, 3453,
3456, 3463, 3479).
SN 2003au (RA = 16h11m11s.56, Dec = +61d15'58".2)
SN 2003au is hosted by NGC 6095, an earliest spiral or a
lenticular galaxy. The expected maximum for typical SN Ia is mag
about 17.2 (vsnet-campaign-sn 564).
UX Ori (RA = 05h04m30s.39, Dec = -03d47'18".3)
The object is now fading to the 10th mag (vsnet-campaign-orion 40).
SN 2003av (RA = 08h01m32s.57, Dec = +02d48'27".9)
SN 2003av is hosted by a dim anonymous galaxy, which is a probable
member of distant cluster (vsnet-campaign-sn 565).
SN 2003aw (RA = 09h05m54s.79, Dec = -05d36'08".6)
SN 2003aw is hosted by a dim galaxy (vsnet-campaign-sn 565).
TmzV868 (RA = 01h47m57s.596, Dec = +56d17'36".85)
T. Kato forwarded the Dr. Samus's comment that the object was
identified with the USNO A1.0 star at the above position, but the
star is actually between GSC 3692.2365 and GSC 3692.946. It would
be likely that the object may not be a Mira-type object as
originally supposed (vsnet-campaign-unknown 191, vsnet-campaign 1371).
QW Ser (RA = 15h26m13s.99, Dec = +08d18'03".8)
As reported by E. Muyllaert on Feb. 23, the SU UMa-type dwarf nova
QW Ser is in outburst. The brightness (12.6mag) may suggest a
superoutburst. Observations by P. Schmeer imply that the
outburst has already been started on Feb. 21 (vsnet-campaign-dn
3482). The last superoutburst occurred in 2002 May
(vsnet-campaign-dn 3470).
AK Cnc (RA = 08h55m21s.21, Dec = +11d18'14".7)
A possible outburst was reported, however, it turned out to be due
to a minor planet (vsnet-campaign-dn 3471, 3472, 3473, 3474, 3475).
SU UMa (RA = 08h12m28s.20, Dec = +62d36'22".6)
As reported by M. Linnolt on Feb. 23, SU UMa is now in a possible
"faint state" (15.3mag) (vsnet-campaign-dn 3478). As commented by
E. Muyllaert, the outburst interval may lengthened. A similar event
occurred in 1997 May - June. (vsnet-campaign-dn 3480, 3481).
YY Her (RA = 18h14m34s.2, Dec = +20d59'21")
L. Smelcer reported an outburst of YY Her (V=11.77 on Feb. 24)
(vsnet-campaign-symbio 46, 47, 48).
CAL 86 (RA = 05h46m18s.2, Dec = -68d35'37")
As reported by R. Stubbings on Feb. 23, the cataclysmic variable
CAL 86 (the X-ray source in the direction of the LMC) is in
outburst. The quiescent magnitude is V=19.0, and the past recorded
outburst was around V=14. The reported brightness surpasses the
recorded outburst (vsnet-campaign-dn 3483).
(continuous targets)
PU CMa (RA = 06h40m47s.67, Dec = -24d23'14".6)
On Feb. 17, the fading seems to have stopped, although the object
was brighter than quiescence (vsnet-campaign-dn 3446). The object
remained the slightly bright state at least for a couple of days
(vsnet-campaign-dn 3457).
AH Her (RA = 16h44m09s.99, Dec = +25d15'02".1)
The standstill continues (vsnet-campaign-dn 3450).
SN 2003ao (RA = 09h45m48s.46, Dec = -14d22'14".0)
It is a type II SN, whose spectrum taken on Feb. 22.30 by the CfA
team is consistent with the plateau phase of normal SN II
(vsnet-campaign-sn 566).
SN 2003ar (RA = 16h02m08s.11, Dec = +70d24'55".5)
A spectrum taken on Feb. 22.50 by the CfA team shows that it was
SN Ia two or three weeks after maximum (vsnet-campaign-sn 566).
SN 2003as (RA = 05h28m45s.81, Dec = +49d52'59".1)
According to the CfA team observation, it is turned out to be a
type-IIn SN. It seemed to belong the luminous class, or "type IIn
hypernova". Followup observations are very urged (vsnet-campaign-sn 566).
beta CMi (RA = 07h27m09s.24, Dec = +08d17'23".4)
While some reports showing possible activities of beta CMi, the
object seems to be normal (vsnet-campaign-be 214, 215, 216, 217,
218, 219, 220, 221, 222, 223, vsnet-campaign-ccd-discussion 42, 43,
44, 45).
SN 2003at (RA = 16h38m47s.81, Dec = +66d01'23".7)
The CfA team spectroscopy revealed that it was a somewhat young
type-II SN on Feb. 22.52 (vsnet-campaign-sn 566).
IGR J16318-4848 (RA = 16h31m48s.47, Dec = -48d49'00".6)
B. Monard reported the detection of the optical counterpart of this
object. The object was reported to be 17.3CR mag on Feb. 4 and 8
(vsnet-campaign-xray 195). T. Kato commented that this object is a
bright object in 2MASS. Since the object lacks a clear signature of
brightening, the identity with the X-ray transient is still unclear
(vsnet-campaign-xray 196).
R CrB (RA = 15h48m34s.40, Dec = +28d09'23".7)
The object is now in a major fading. The fading rate is
increasing with time. Observations are encouraged
(vsnet-campaign-rcb 99, 100, 102, 103).
GZ Cnc (RA = 09h15m51s.70, Dec = +09d00'50".2)
The object again experienced an outburst (13.3mag) on Feb. 20 as
reported by M. Simonsen. The last outburst occurred on Feb. 10
(vsnet-campaign-dn 3458). The light curve on Feb. 20 from the
Nyrola team showed clear presence of intermediate-period (around 40
min) variations. The profile even looks "miniature" superhumps.
There was no indication of the presence of short-period flare-like
oscillations (vsnet-campaign-dn 3462, 3468). The object was still
bright on Feb. 21 (vsnet-campaign-dn 3461). It then started fading
(vsnet-campaign-dn 3477).
MisV1147 (RA = 22h54m03s.78, Dec = +58d54'02".1)
Another fading (14.8mag) was reported on February 17
(vsnet-campaign-unknown 189). It further faded to 15.5mag on
Feb. 18 (vsnet-campaign-unknown 190).
*** Future schedule ***
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]
[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]
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 ***
KS UMa
Light curve by T. Vanmunster:
http://vsnet.cbabelgium.com
[vsnet-campaign-dn 3451, 3452, 3466]
VSNET page:
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/DNe/ksuma.html
Superhump profile:
http://vsnet.kusastro.kyoto-u.ac.jp/DNe/KS_UMa/kssh.gif
[vsnet-campaign-dn 3469]
Time-series data by L. Kral, see [vsnet-campaign-data 109]
(This summary can be cited.)
Regards,
Makoto Uemura
Return to the Powerful Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
