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[vsnet-campaign-news 9] News from VSNET No. 9
*** News from VSNET ***
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.
Regards,
Taichi Kato
On behalf of the VSNET administrator team
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Several interesting dwarf novae are reported in outburst, and followed
by a number of observers. 1432-0033 is among such objects, which had been
discovered as a cataclysmic variable during the optical quasar survey
by Berg et al. The importance of the system soon brought the VSNET members
to monitor potential outbursts. The first-ever outburst was caught in
1999 May by Rod Stubbings (see also vsnet-alert 2965,
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/alert2000/msg00965.html).
The outburst in 1999 had all characterstics of an SU UMa-type superoutburst:
what solely missing was the confirmation of superhumps. Those who may
be interested in superhumps and SU UMa stars, please refer to:
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/DNe/superhump.html
The 2000 June - July outburst of 1432-0033, detected again by the VSNET
member Rod Stubbings, has brought an excitement among observers: the system
turned out to be a rare, eclipsing SU UMa-type dwarf nova in superoutburst
(for more information of the discovery process, refer to the vsnet-campaign
archive). Eclipsing systems among SU UMa-type dwarf novae have been
providing unique information of the outbursting accretion disk through the
analysis of eclipse light curves.
Good recent examples of eclpsing SU UMa-type dwarf novae, followed by
the VSNET Collaboration team, can be found at:
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/DNe/tmvz85.html
(TmzV85 = IY UMa, recently discovered eclipsing SU UMa-type dwarf nova,
originally reported by Kesao Takamizawa as a possible dwarf nova).
and
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/DNe/dvuma9912.html
Other potentially interesting objects include V344 Pav, a good superoutburst
candidate, but was never observed photometrically in the past.
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).
VSNET has been also undertaking an extensive identification program
of ROSAT sources, from which a number of new interesting (and often
overlooked) targets have emerged. Please look at these objects, and report
us when an outburst is detected! The recently discovered Galactic microquasar
LS 5039 has been also discussed in vsnet-chat.
VSNET has initiated a number of special mailing lists, some of which are
sub-lists of vsnet-alert and vsnet-outburst (i.e. relaying new events!)
vsnet-rcb (R CrB stars)
vsnet-symbio (symbiotic variables or Z And type variables)
If one wish to subscribe to any of new lists, send a message to
vsnet-adm@kusastro.kyoto-u.ac.jp with a body line (for example)
SUBSCRIBE vsnet-rcb your e-mail address
SUBSCRIBE vsnet-symbio your e-mail address
etc.
We have created a list in Japanese "vsnet-j". Those who can handle
Japanese are welcome to join the list.
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The following was issued on Jul. 3, 2000, as VSNET campaign circulation 288.
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
1432-0033 (RA = 14h35m00.14s, Dec = -00d46'07".0)
In response to the outburst (14.9mag on June 24) reported by
R. Stubbings (vsnet-alert 5030), T. Vanmunster observed it, and
the resultant light curve clearly showed a superhump-like profile with
an amplitude of about 0.6 mag (vsnet-alert 5037, vsnet-campaign 257).
In Astrophys. J. Sup. 78, 409, 1992, Berg et al. mentioned this object
as an emission-line CV, with a "resemblance to HT Cas and U Gem".
The reported quiescent magnitude is 18.5. As reported by T. Vanumuster
in [vsnet-alert 5052], the system has been confirmed to be a genuine
eclipsing SU UMa-type dwarf nova, which had been suggested from quiescent
spectroscopy and recent superhump amplitude (vsnet-campaign 279).
It is still in the superoutburst.
Eclipse observations are essential to study the accretion disk structure.
V1504 Cyg (RA = 19h28m55.87s, Dec = +43d05'39".9)
As reported in [vsnet-alert 5050], M. Simonsen reports the SU UMa-type
dwarf nova, V1504 Cyg is still bright (14.2mag on June 30), indicating
that the present outburst is a superoutburst. The SU UMa-type nature
of V1504 Cyg has been confirmed, but detailed observations are still needed.
It is still in the superoutburst.
Observations are encouraged to study the superhump evolution.
V344 Pav (RA = 19h16m10.21s, Dec = -62d35'54".4)
R. Stubbings reported that the dwarf nova V344 Pav is undergoing a
rare outburst (14.6mag on July 2). The last reported outburst occurred
in 1999 September - October, whose fading trend closely resembled that
of a superoutburst of an SU UMa-type dwarf nova. The large outburst
amplitude (more than 6 mag) also supports this possibility.
Time-series photometry during the present outburst is strongly
recommended (vsnet-alert 5055, vsnet-campaign 281).
BF Ara (RA = 17h38m10.40s, Dec = -47d10'43".4)
The dwarf nova BF Ara is reported to be undergoing a long, bright
outburst. At least one report (IBVS 2286) reported the possible
presence of a superhump. The interval of outbursts as short as 7 d
is also rather exceptional for an SS Cyg-type star. Since BF Ara had
a bright outburst in April, this star, if confirmed to be an SU UMa-type
dwarf nova, may be the first southern ER UMa star (vsnet-campaign 286).
Observations are strongly encouraged.
(continuous targets)
CI Aql (RA = 18h52m03.6s, Dec = -01d28m38.9s)
The plateau stage continues (vsnet-campaign-nova 14). The data
obtained by G. Masi shows a relatively monotonous decline of 0.2 mag
between 20.947 and 21.066 UT. The trend is consistent with the
eclipse phase, just prior to the predicted primary minimum
(vsnet-campaign-nova 5). Interrupting the plateau stage, the
slightly rising was confirmed through the data on June 30 from Kyoto
observations (vsnet-campaign-nova 15). The observation on July 1 at
Kyoto has again caught the fading of CI Aql. A sharp ingress
(0.3 mag in 2 hours) to the predicted primary eclipse is recorded
(the minimum somewhat slower than the prediction), while the egress
was slower (vsnet-campaign-nova 16).
The current magnitude is about 12.2mag. The observations of
any phase are strongly encouraged.
RX J1450.5+6403 (RA = 14h50m38.4s, Dec = +64d03'29")
On June 26, T. Vanmunster confirmed the outburst (15.9mag), which
implied the outburst was short and faint (vsnet-campaign 258).
The observation on June 27 by A. Henden also agree with the decline
trend (vsnet-campaign 259). T. Vanmunster additionally reported his
pre-outburst observations in [vsnet-campaign 263].
Now it is in quiescence.
SN2000cr (RA = 13h58m38.4s, Dec = +37d26'12.9")
The magnitude of this supernova reached the peak around June 28.
at 15mag (vsnet-campaign-sn 7). Observarions are encouraged.
V1493 Aql
In IAUC 7443, R. Novak et al. reports the presence of a period of
0.156 +/- 0.001 d, with a possible presence of eclipses with a depth
of 0.014 mag (vsnet-campaign-nova 7).
V803 Cen (RA = 13h23m44.5s, Dec = -41d44'30".1)
From the observations on June 26 and 27, if the present supercycle
still holds (IBVS 4915), the object may enter the decline stage
(vsnet-campaign 262). The same tendency was observed on June 29
(vsnet-campaign 269). W. Walker reported V803 Cen is still in its
cycling state (vsnet-campaign 271). It is then bright again on July 2
at 13.6 mag (vsnet-campaign 285).
The fluctuation is still seen. Keep attention on this active phase.
PKS2005-489 (RA = 20h05m47.4s, -48d58'45".0)
The brightening of this blazer continues (vsnet-campaign-blazer 7).
B. Monard updated the comparison sequence in view of the actual
Tycho 2 value of the brighter star, and also mentioned that a similar
brightening to the current one was observed three (or four?) years
ago (vsnet-campaign-blazer 8).
BL Lac (RA = 22h02m42.86s, Dec = +42d16'37.6")
Recent observations suggest BL Lac may be slightly active
(than May and early June) (vsnet-campaign-blazer 11). Slightly
active state still continues (vsnet-campaign-blazer 12).
XTE J1118+480 (RA = 11h18m10.9s, Dec = +48d02'12".9)
A rapid fading feature was seen in the data on June 30 obtained
at Kyoto (vsnet-campaign 277). The data on July 1 agree with this
trend (vsnet-campaign 278).
The gentle decline trend continues, and the humps are prominent.
Observations of any duration are encouraged.
V436 Cen (RA = 11h13m58.2s, Dec = -37d40'45".0)
The bright superoutburst of V436 Cen is apparently ending (13.0mag
on July 2). Please look for the late-stage phenomenon (rebrightenings etc.)
(vsnet-campaign 283).
(outburst predictions)
V844 Her (RA = 16h25m01.69s, Dec = +39d09'25.9")
As predicted by T. Watanabe in [vsnet-future 12], the next outburst
of the unique SU UMa-type dwarf nova V844 Her is predicted to occur
within two weeks! Because of its best seasonal visibility, we should
put this target on the potential campaign list (vsnet-campaign 272).
V1028 Cyg (RA = 20h00m52.13s, Dec = +56d56'22.3")
As predicted by T. Watanabe-san in [vsnet-future 13], there is a small
chance of the next outburst of the short-period SU UMa-type dwarf nova
V1028 Cyg within two days! (He tells if it doesn't occur, we will probably
have to wait September). Because of its best seasonal visibility, we may
put this target on the potential campaign list (vsnet-campaign 273).
(new objects for long-term monitoring)
MT Pup (RA = 07h54m11.9s, Dec = -14d39'16")
T. Kato has noticed the neglected CV, MT Pup with a large amplitude
during the course of ROSAT source identification and suggest to put
this on long-term monitoring program to clarify the nature of variability
(vsnet-campaign 274). Registered as a large-amplitude eclipsing binary
in GCVS, but the X-ray is exceptionally strong. Please note MT Pup was
once suspected to be an R CrB star.
SY Cir (RA = 14h03m44.9s, Dec = -69d37'31")
During the ROSAT identification, T. Kato has noticed this object,
and suggest to put it on long-term monitoring program. The
identification is not secure. Since several RV Tau candidates later
turned out to be CVs, this object would deserve further dense observations
(vsnet-campaign 275).
EO Oph (RA = 17h00m30.3s, Dec = -26d45'10")
Another noteworthy ROSAT identification. The identification looks
secure, but the color and recorded variability in MISAO data more
suggest a Mira star. There may be a chance coincidence of an X-ray
emitting object, but the possibility of a peculiar object is not
excluded (vsnet-campaign 276).
NSV00907 (RA = 02h44m57.3s, Dec = +27d31'13")
and NSV01436 (RA = 02h44m59.1s, Dec = +27d31'25")
As reported in vsnet-chat, two NSV stars possibly identified with ROSAT
sources (possible dwarf novae) are introduced to our long-term campaign
program to look for the possible next outburst.
*** Future schedule ***
BL Lac campaign (July 17 - August 11)
Massimo Villata, Gino Tosti, and Enrico Massaro organize an
optical campaign on BL Lac contemporaneous with the high-energy
campaign involving X-ray and TeV observatories such as BeppoSAX,
RXTE, STACEE, CAT, HEGRA. Their goal is high-density and
high-precision coverage, possibly in two optical bands (B and R).
Observers interested in participating to this optical campaign are
invited to contact with M. Villata (villata@to.astro.it).
[vsnet-campaign 204]
NY Ser spectroscopic observations at the Calar Alto Observatory
(July 08/09 and 09/10)
D. Nogami noticed their schedule of spectroscopic observations of
NY Ser and wrote: "Because it is quite important for us to know the
state of NY Ser at our observations as accurately as possible, we would
ask observers to make a close monitor of this star for ~1 month from now."
For more information, please see [vsnet-campaign 265], or contact
with D. Nogami (daisaku@uni-sw.gwdg.de).
[vsnet-campaign 265]
*** General information ***
V803 Cen
preprint (IBVS No. 4915)
The text is on [vsnet-preprint 3], which will become available at
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-preprint/msg00003.html
The LaTeX source and PostScript figures are available from
http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/preprints/V803_Cen/
and GIF figures (possibly more convenient for many browsers):
http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/preprints/V803_Cen/fig1.gif
http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/preprints/V803_Cen/fig2.gif
CI Aql
eclipse ephemeris, see [vsnet-campaign-nova 12]
(This summary is reproduction free.)
Regards,
Makoto Uemura
vsnet-adm@kusastro.kyoto-u.ac.jp
Return to Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
VSNET Home Page