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[vsnet-campaign-news 157] News from VSNET
*** News from VSNET ***
V359 Cen turns out to be a long-period SU UMa star with a
long supercycle.
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 June 3, 2002, as VSNET campaign circulation 1315
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
V359 Cen (RA = 11h58m15s.29, Dec = -41d46'07".9)
On May 28, R. Stubbings reported an outburst of the dwarf nova
V359 Cen. The object had been regarded as a possible nova until the
discovery of an outburst in 1999 July by R. Stubbings. The last
outburst was detected by R. Stubbings on 2001 April 25
(vsnet-campaign-dn 2465). R. Santallo performed time-series
photometry on May 31. His observation detected a fully developed
superhump signal with an amplitude of 0.30 mag. The light curves
indicate that the period is 0.08152(1) d, which makes V359 Cen as
one of below-the-gap SU UMa-type systems with the longest orbital
periods (vsnet-campaign-dn 2491, 2492). The object might belong to
a sub-class including EF Peg and V725 Aql, both of which show
unusually infrequent outbursts for their superhump period
(vsnet-campaign-dn 2494). There may be even a hint of super-QPOs in
the May 29 light curve taken by P. Nelson. T. Kato reported that
the superhump period decreased at least during the early part of
this superoutburst (vsnet-campaign-dn 2502, 2505). The outburst is
now ongoing (vsnet-campaign-dn 2468, 2482, 2499).
TV Crv (RA = 12h20m23s.56, Dec = -18d27'02".7)
R. Stubbings detected an outburst (13.1mag) on May 30. TV Crv is
an SU UMa-type dwarf nova with relatively rare outbursts. The last
outburst (superoutburst) was reported in 2001 February
(vsnet-campaign-dn 2473). The Kyoto team detected superhumps with
amplitudes of 0.15-0.20mag on June 2 (vsnet-campaign-dn 2507). The
superoutburst continues (vsnet-campaign-dn 2486, 2501).
QW Ser (RA = 15h26m13s.99, Dec = +08d18'03".8)
An outburst of 13.2mag was detected on May 29 by R. Stubbings.
The object was then reported to further brighten, which indicates
that the current outburst is a superoutburst (vsnet-campaign-dn
2478). The Kyoto team detected fully developed superhumps with
amplitudes of 0.3-0.35mag on June 2 (vsnet-campaign-dn 2506). The
superoutburst is now ongoing (vsnet-campaign-dn 2485, 2500).
HS Vir (RA = 13h43m38s.5, Dec = -08d14'04".1)
An outburst of 14.2-14.0mag was reported on May 28 by R. Stubbings
(vsnet-campaign-dn 2466).
CL Pup (RA = 07h30m01s92, Dec = -19d28'01".2)
A bright outburst (13.8-13.7mag) was reported on May 29
(vsnet-campaign-dn 2469). The object remained bright on May 30
(vsnet-campaign-dn 2474).
CH Cyg (RA = 19h24m33s.07, Dec = +50d14'29".5)
CH Cyg is rather rapidly fading. Similar systematic fadings were
observed in 1999 June and 2000 May (vsnet-campaign-symbio 16).
Z Cha (RA = 08h07m16s.29, Dec = -76d32'20".9)
An outburst (12.3-12.4mag) of the eclipsing SU UMa star, Z Cha was
reported on May 31 by R. Stubbings (vsnet-campaign-dn 2476). The
outburst still continues, which indicates that the current outburst
must be a superoutburst (vsnet-campaign-dn 2504).
SN 2002de (RA = 16h16m30s.38, Dec = +35d42'30".2)
This SN appeared in NGC 6104, whose recession velocity is about
8400 km/s. The observed magnitude is somewhat brighter than
expected maximum of normal SN Ia (vsnet-campaign-sn 433).
TK5 (RA = 19h17m26s.5, Dec = +37d10'41")
An outburst of 14.8mag was reported on June 1 by C. P. Jones
(vsnet-campaign-dn 2480). T. Vanmunster performed time-series
photometry and reported a flat light curve with no relevant
modulations (vsnet-campaign-dn 2487, 2493).
RY Ser (RA = 17h23m07s54, Dec = -12d47'44".0)
R. Stubbings detected an outburst (13.4mag) of this possible UGSS
type star on May 31 (vsnet-campaign-dn 2481). The object was still
in outburst on June 1 without significant fading (vsnet-campaign-dn
2488).
NSV 10934 (RA = 18h40m52s.26, Dec = -83d43'10".24)
An outburst (12.9mag) of this NSV/ROSAT dwarf nova was reported on
June 2 by R. Stubbings. The last outburst was seen in 2002 April
(vsnet-campaign-dn 2495).
V1830 Sgr (RA = 18h13m51s, Dec = -27d42'23")
R. Stubbings detected a 12.7mag outburst on June 2. Although the
object is likely a UGSS star as judged from the outburst pattern,
the large outburst amplitude would make it a potentially interesting
target for further photometric study (vsnet-campaign-dn 2496).
Suspected variable (nova?) in M7
J. M. Fernandez observed a ~7mag object, which is possibly
identified with GSC 7386 355 (vsnet-campaign-unknown 70). The 2MASS
color is not red, indicating that the object is not a (late-type)
flare star. Furthermore, the ROSAT hardness ratios are relatively
hard (unlike flare stars), possibly suggesting that something
unusual may be taking place (vsnet-campaign-unknown 69).
(continuous targets)
V4641 Sgr (RA = 18h19m21s.6, Dec = -25d24'25")
Observations by R. Santallo on May 25 detected steadily increasing
activity, which smoothly evolved into the violent state later on May
25 (vsnet-campaign-v4641sgr 67). Short-term fluctuations weakened,
or disappeared on May 27 (vsnet-campaign-v4641sgr 65, 66). On May
29, M. Uemura reported a gradual brightening which was probably a
part of normal elliptical modulations observed at quiescence
(vsnet-campaign-v4641sgr 68, 70). C. Markwardt reported that the
majority of the X-ray violent flaring activity was on May 24-25, but
that there was one large (May 26.65 UT) and several small X-ray
flares on May 26 (vsnet-campaign-v4641sgr 69). Possible
fluctuations were reported on June 2 (vsnet-campaign-v4641sgr73).
The object has remained at quiescence (vsnet-campaign-v4641sgr 71,
72).
SN 2002by (RA = 17h50m18s.58, Dec = -59d33'51".6)
According to IAUC 7910, the spectrum of SN 2002by was taken at
Siding Spring Observatory on May 18.53UT, which revealed that it is
of type Ia, about 2 months after maximum. Thus, the discovery,
which made on Mar. 31 UT, was at around maximum phase
(vsnet-campaign-sn 431).
V504 Cen (RA = 14h12m49s.36, Dec = -40d21'02".2)
The faint state still continues (vsnet-campaign-nl 86).
SN 2002cv (RA = 10h18m03s.68, Dec = +21d50'06".2)
The infrared spectrum of SN 2002cv taken on May 22.3-23.3 at UKIRT
shows it is of type Ia around B maximum. There is some resemblance
with intrinsically brighter SN Ia 1991T, though SN 2002cv is
reddened by A(V) about 6 mag (vsnet-campaign-sn 432).
PU CMa (RA = 06h40m47s.67, Dec = -24d23'14".6)
The outburst is ongoing, but has become slightly fainter
(vsnet-campaign-dn 2463, 2472).
V844 Her (RA = 16h25m01s.69, Dec = +39d09'25".9)
The object entered a rapid fading phase from superoutburst
(vsnet-campaign-dn 2467, 2470, 2479).
MV Lyr (RA = 19h07m15s.93, Dec = +44d01'10".7)
The object has remained at the faint state (vsnet-campaign-nl 85).
OY Car (RA = 10h06m22s.46, Dec = -70d14'04".4)
The object is fading from the superoutburst (vsnet-campaign-dn
2464, 2483, 2498).
V803 Cen (RA = 13h23m44.5s, Dec = -41d44'30".1)
V803 Cen is undergoing a bright outburst (likely superoutburst),
which was detected on May 29 by R. Stubbings (vsnet-campaign-dn
2471). The last superoutburst started on March 21, making a
supercycle length of ~70 d. This value is quite characteristic to
the "ER UMa-type" outburst pattern of V803 Cen seen in 1998-1999.
After "standstills" in 2000 and 2001 (IBVS 5091), the star has
resumed its ER UMa-type activity. The present observation makes the
similarity between V803 Cen and CR Boo more concrete than ever
(vsnet-campaign-dn 2475). The outburst is now ongoing
(vsnet-campaign-dn 2489, 2503).
V Sge (RA = 20h20m14s.75, Dec = +21d06'09".0)
The object was reported to further brighten since around May 27
(vsnet-campaign-nl 84).
CR Boo (RA = 13h48m55s.42, Dec = +07d57'30".3)
The object again brightened on May 31 (13.7mag) and June 1
(13.5mag)(vsnet-campaign-dn 2490).
V2051 Oph (RA = 17h08m19.1s, Dec = -25d48m31.1s)
The object is still on the long fading tail at about 15mag
(vsnet-campaign-v2051oph 20).
*** Future schedule ***
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]
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]
Blazar meeting at Tuorla: June 17-21, 2002
for more information, see http://vsnet.astro.utu.fi/blazar02
[vsnet-campaign-blazar 232]
*** General information ***
V4641 Sgr
X-ray light curve with RXTE/PCA:
http://lheawww.gsfc.nasa.gov/users/swank/v4641sgr/
[vsnet-campaign-v4641sgr 69]
V359 Cen
Superhump light curve:
http://vsnet.kusastro.kyoto-u.ac.jp/pub/vsnet/DNe/V359_Cen/v359sh.gif
[vsnet-campaign-dn 2492]
Z Cha
Eclipse ephemeris, see [vsnet-campaign-dn 2477]
OY Car
Eclipse ephemeris, see [vsnet-campaign-dn 2484]
Please discard vsnet-campaign-v838mon 371 and 372, because they
contained a virus (W32/Klez).
(This summary can be cited.)
Regards,
Makoto Uemura
Return to Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
VSNET Home Page