[Message Prev][Message Next][Thread Prev][Thread Next][Message Index][Thread Index]
[vsnet-campaign-news 10] News from VSNET No. 10
*** 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
----------------------------------------------------------------------------
Several interesting dwarf novae are reported in outburst, and followed
by a number of observers. QW Ser is a very intersting example. The object
was first discovered as a likely dwarf nova by the Kesao Takamizawa, and
was called as TmzV46. Since the discovery announcement in VSNET, the star
had been regularly monitored by a number of observers, including Patrick
Schmeer, one of the world most enthusiastic dwarf nova observers, who
discovered a brightening in 1999 October. This outburst was confirmed
by a number of observers, including the Kyoto University team, which led
to the permanent variable star designation "QW Ser" given by the General
Catalogue of Variable Star (GCVS) team. Patrick Schmeer and other observers
continued observations of this star and found the next bright outburst
in July. Subsequent CCD observation by Rudolf Novak (Nicholas Copernicus
Observatory, Czech) cofirmed the presence of superhumps, which first firmly
identified the object as a genuine SU UMa-type dwarf nova. The international
observing campaign, led by Rudolf Novak, is still ongoing. Please come
and join the work! 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
Several new ROSAT (X-ray satellite) cataclysmic variables are caught in
outburst (the object starting with "RX J"). Monitoring such dwarf nova
candidates selected by ROSAT is a very good project for both visual and
CCD observers. VSNET members have had much success in this field, and
greatly contributed to the understanding the nature of these X-ray sources.
See individual messages for more description of each target. We have
also created a new mailing list devoted to ROSAT identifications (see below).
The famous dwarf nova SS Cyg was caught in its rise to outburst, and
timely reported to the VSNET. This object has been on target-of-opportunity
(TOO) programs of several satellites, and this discovery and immediate
notification through the internet at the early epoch of outburst greatly
contributed to initiate multiwavelength satellite observations.
Eclipses in CI Aql = the recurrent nova Aql 1917,2000 have been perfectly
established by a number of observers, including Katsura Matsumoto (Kyoto
University), the CI Aql internation campaign leader. The object has been
staying at its "plateau" stage, during which the nova fading apparently
stops. Time-series CCD observations at all binary phases would clarify
the evolution eclipse profile toward the final fading stage, necessary for
clarifying the mechanism of the recurrent nova.
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).
*** Mailing Lists of the Week ***
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-lpv (Long-period variables (Mira stars) event news)
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-lpv/msg00001.html
vsnet-rvtau (RV Tau stars event news)
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-rvtau/msg00001.html
vsnet-nl (Novalike variables - a class of cataclysmic variables)
[Note: The scientific term "novalike" (or NL) has no relation to nova
explosions. This does not mean stars which undergo explosive events
resembling nova explosions, nor possible novae.]
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-nl/msg00001.html
vsnet-polar (Polars - a class of magnetic cataclysmic variables)
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-polar/msg00001.html
vsnet-orion (Pre-main sequence variables; T Tau stars and Orion variables)
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-orion/msg00001.html
vsnet-be (Be stars; gamma Cas stars)
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-be/msg00001.html
vsnet-gcvs (GCVS/NSV revision project)
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-gcvs/msg00001.html
vsnet-id-rosat (ROSAT identification)
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-id-rosat/msg00001.html
And a new list of general interest. Variable star observers are usually
frequent visitors to deep-sky objects. Please join us to exchange
information!
vsnet-deepsky (Deep-sky objects, including quasars, galaxies, clusters,
double stars, exotic stars etc.)
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-deepsky/msg00001.html
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-deepsky your e-mail address
SUBSCRIBE vsnet-lpv your e-mail address
etc.
Or, look at the list information page for more details:
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/information.html
----------------------------------------------------------------------------
The following was issued on Jul. 10, 2000, as VSNET campaign circulation 350.
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
QW Ser (RA = 15h26m13.99s, Dec = +08d18'03".8)
P. Schmeer has caught a bright outburst of QW Ser, originally known as
TmzV46 which was a candidate of SU UMa-type dwarf nova (vsnet-campaign 302).
P. Schmeer confirmed the outburst at 12.88mag on July 6.18
(vsnet-campaign 309). CCD photometry performed by R. Novak at Nicholas
copernicus observatory definitely showed the superhumps and established
that it is a new SU UMa-type dwarf nova (vsnet-campaign 317,
vsnet-alert 5072). He reported the superhump period and the amplitude
in [vsnet-alert 5073], and later revised the value to be the period of
0.0773(1) and amplitude of 0.15(2) mag (vsnet-campaign 327). E. Pavlenko
reported their observations which yielded the superhump amplitude to be
0.15mag and the period to be 0.070+-0.003d (vsnet-campaign 324).
G. Masi reported his light curve which showed another short hump on
normal superhump light curve (vsnet-campaign 348, vsnet-campaign-data 10).
Now it is still in superoutburst and the current magnitude is about
12.7mag. Time-series observations are strongly urged.
NY Ser (RA = 15h13m02.39s, Dec = +23d15'07".1)
D. Nogami and his collaborators have carried out spectroscopic
observations of NY Ser during July 08/09 and 09/10 nights, and found
this star to be in outburst in both nights (for more details, see below
"*** Future schedule ***") (vsnet-campaign 349).
It is possible that they succeed in taking the spectra around the
maximum of outburst. Follow-up observations are strongly urged.
MM Sco (RA = 17h30m45.68s, Dec = -42d11'09".2)
MM Sco further brightened at 13.3mag on July 5. The present brightness
has reached that of the long, bright outburst in 1998 July. It is likely
a long-period SS Cyg star (long outbursts only), but there may not have
been an attempt to check short-term variability during outburst
(vsnet-campaign 305). Now it is still in the outburst.
The star possibly needs outburst astrometry, since the crowded field has
made unambiguous identification a bit difficult.
MKN421 (RA = 11h04m27s, Dec = +38d12'32")
The blazar MKN421 (Markarian 421) has remarkably faded since the end of
June. The present level of faintness was only attained in early 1996
(vsnet-campaign-blazer 15). D. Rodriguez reported his CCD observation
of V=13.5mag, which confirmed the tendency (vsnet-campaign-blazer 16).
The fading trend is still ongoing. The current magnitude is about
13.5mag. Please keep attention.
RX J1155.4-5641 (RA = 11h55m27.6s, Dec = -56d41'48")
B. Monard reported the suspected ROSAT CV, RX J1155.4-5641 has shown
a sudden brightening from 14.4mag on July 1 to 12.5mag on July 4.
T. Kato noticed that the decline rate more suggests an SS Cyg-type
outburst (vsnet-campaign 312). The object reached its peak of 12.2mag
on July 4, and then, began fading.
HadV62 (RA = 18h32m18.4s, Dec = -26d30'14")
K. Haseda reported the discovery of a new variable star (HadV62).
The amplitude suggests a Mira star, but the absence of the image on the
RealSky (confirmed by Haseda), likely identifications with the blue
Tycho2 (but missing on GSC) star, and the absence of an IRAS source which
is expected for this bright variable, is unusual (vsnet-alert 5077).
On the basis of the unfiltered CCD observation by Kyoto team, T. Kato
suggested it is a relatively red star (vsnet-alert 5085). He also noticed
that HadV62 is possibly identified with V1901 Sgr (vsnet-alert 5086).
The current magnitude is about V=11.8mag.
RX J2315.5-3049 (RA = 23h15m31.93s, Dec = -30d48'47".0)
As reported in [vsnet-outburst 245] by R. Stubbings, the ROSAT-selected
dwarf nova candidate RX J2315.5-3049 is undergoing the first-ever
detected outburst. Stubbings reported that the star was at mv=13.4 on 2000
July 8. The outburst amplitude is thus about 4 mag (vsnet-campaign 338).
Now it is in outburst. Observations are encouraged.
(continuous targets)
CI Aql (RA = 18h52m03.6s, Dec = -01d28m38.9s)
The fading observed at Kyoto on July 4 well correspond to the primary
minimum, and variations between nights almost certainly reflect orbital
modulations (vsnet-campaign-nova 30). A sharp peak was observed around
MinII on July 5 (vsnet-campaign-nova 32). The observation on July 3 by
S. Kiyota confirmed the secure appearance of primary eclipses
(vsnet-campaign-nova 33, vsnet-campaign-data 7). L. Kral caught the
whole primary eclipse on July 5/6 and reported the eclipse depth of about
0.2mag and the duration of about 2.3 hours (vsnet-campaign 314,
vsnet-campaign-data 8).
Observations at other longitudes and other phases are strongly encouraged.
1432-0033 (RA = 14h35m00.14s, Dec = -00d46'07".0)
This new eclipsing SU UMa-type dwarf nova slightly faded from the
superoutburst since June 24, but observations are strongly urged
(vsnet-campaign 297).
V1504 Cyg (RA = 19h28m55.87s, Dec = +43d05'39".9)
On July 6, E. Pavlenko reported that this SU UMa-type dwarf nova was
still undergoing the superoutburst with the mean period 0.07d, as it was
found by D. Nogami earlier, and amplitude, which evolved from 0.25 mag
to 0.15 mag during 5 days since the beginning of the superoutburst.
She noticed that ~1' to the North from V1504 Cyg, there is another
variable star which should not use as the comparison star
(vsnet-campaign 301).
V344 Pav (RA = 19h16m10.21s, Dec = -62d35'54".4)
The outburst of this possible SU UMa-type dwarf nova is ongoing.
A. Pearce reported the last negative observation before the outburst
of <15.2mag on June 29.843 (vsnet-campaign 289). The superoutburst
was interrupted by a rapid fading since July 8 (vsnet-campaign 339).
BF Ara (RA = 17h38m10.40s, Dec = -47d10'43".4)
This possible first southern ER UMa star is still in the long
outburst since June 29 (vsnet-campaign 347).
It is now still in outburst. The current magnitude is about 14.7mag.
More observations are strongly encouraged.
V803 Cen (RA = 13h23m44.5s, Dec = -41d44'30".1)
The helium dwarf nova V803 Cen has become even brighter on July 4.382
(13.2 mag)(vsnet-campaign 299). It faded at 14.0mag on July 4.698,
and then, brightened again at 13.2mag on July 6.417 (vsnet-campaign 322).
Time-resolved photometry during the present stage is very important.
PKS2005-489 (RA = 20h05m47.4s, -48d58'45".0)
The blazar PKS 2005-489 was reported to be fading from the current
bright state (12.3mag on June 29 - 12.8mag on July 4)
(vsnet-campaign-blazer 18).
BL Lac (RA = 22h02m42.86s, Dec = +42d16'37.6")
S. Bloom reported his CCD observation of V=14.2 and R=13.6 on July 3
in [vsnet-campaign-blazer 13], indicating that a slightly active phase
is still ongoing. A fading ( <15mag ) has been observed since July 3
(vsnet-campaign-blazer 20).
XTE J1118+480 (RA = 11h18m10.9s, Dec = +48d02'12".9)
From the data during JD2451720 - 2451730 observed by VSNET collaboration
team, it was revealed that humps are still prominent with the amplitude
of about 0.08 mag and their profile is roughly sinusoidal. The object
keeps its gradual fading (0.06 mag/d) (vsnet-campaign 328).
More time-series observations are encouraged.
V382 Vel (RA = 10h44m48.4s, Dec = -52d25'31")
A possible variability was noticed in [vsnet-campaign-nova 21],
however, M. Morel (vsnet-campaign-nova 23) and B. Monard
(vsnet-campaign-nova 24) commented that there must be a difference
in the sequence used among observers. A. Retter additionally commented
that the nova, still bright at mV=10.5-11.0 is a very promising object
to search for periodicities even if the apparent oscillation was
spurious (vsnet-campaign-nova 28). S. Otero suggested that
GSC 8210-00897 is the most suitable comparison star (vsnet-campaign-nova 29).
A few long continuous nights with a CCD might be useful.
(outburst predictions)
V893 Sco
T. Kato reported in [vsnet-campaign 313] that the next outburst of
V893 Sco is expected and the observations are strongly encouraged.
(about eclipse ephemeris, see below)
*** 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 (this article was posted on June 29)."
For more information, please see [vsnet-campaign 265], or contact
with D. Nogami (daisaku@uni-sw.gwdg.de).
[vsnet-campaign 265]
V446 Her campaign (throughout this summer)
Boris T. Gaensicke organize a campaign on the post nova V446 Her (V~18).
Their aim is to obtain a *good* contiguous light curve of V446 Her that
covers 2-3 dwarf nova-like outbursts of the system, in order to compare
its outburst characteristics to those of ``normal'' dwarf novae.
They invite those of you equipped with a CCD camera to obtain a couple
of images of V446 Her per night throughout the next three months, say,
until the end of September.
For more information, please see [vsnet-campaign 325] or contact
with Boris T. Gaensicke (boris@uni-sw.gwdg.de).
*** General information ***
RX J1450.5+6403
The following sequence has been made available by courtesy of Dr. Henden:
http://ftp.nofs.navy.mil/pub/outgoing/aah/sequence/j1450.dat
(vsnet-campaign 295)
QW Ser
The following sequence has been made available by courtesy of Dr. Henden:
http://ftp.nofs.navy.mil/pub/outgoing/aah/sequence/qwser.dat
(vsnet-campaign 308)
Light curve by R. Novak can be seen in [vsnet-campaign 327]
Light curve by J. Pietz can be seen at:
http://home.t-online.de/home/Jochen.Pietz/qwser.gif
Light curve by G. Masi can be seen at:
http://vsnet.eurolink.it/comets/qwser.gif
V893 Sco
Eclipse ephemeris: see [vsnet-campaign 313]
CI Aql
Light curve by L. Kral:
http://ostrava.astronomy.cz/stars/ciaql/cien.htm
(vsnet-campaign 314)
(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