[Message Prev][Message Next][Thread Prev][Thread Next][Message Index][Thread Index]
[vsnet-campaign-news 12] News from VSNET 12
*** 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
----------------------------------------------------------------------------
The most spectacular event of this week is the historical outburst of
delta Scorpii! Delta Scorpii is a bright naked-eye star, which forms
the center of the three stars making the western border of the constellation.
A catastrophe is occurring in this star!!
The first observer who noticed the change of this star was Sebastian
Otero (Argentina), an intensive observer of the VSNET. Otero reported to
VSNET that the star looks brighter than normal, and called for spectroscopic
observation. Upon this notification, a group led by Spanish astronomer
Fabregat confirmed the dramatic change in the star's spectrum. The object
had no or little emission lines in the past, but the present observation
confirmed the emergence of emission lines. The star was thus identified
as a genuine Be (B-star with emission lines) star. Ths star is presently
reported as magnitude 1.9 and looks like to brighten further, reported to
have changed the impression of the constellation!
Such a striking outburst of a Be star is next the the spectacular event
of gamma Cas in 1937 April, 63 years back! Please closely look at this
naked-eye object (no telescope is necessary!) and report your observations
to VSNET.
The key subscription lists are vsnet-be and vsnet-campaign-be.
To subscribe, please send "vsnet-be and vsnet-campaign-be" to
vsnet-adm@kusastro.kyoto-u.ac.jp
Supernova 2000cx is another spectacular object. This object is confirmed
to be a very luminous class of supernova type Ia. The object now reaches
magnitude 13.5, and is a good target for deep-sky hunting!
Several interesting dwarf novae are reported in outburst, and await
follow-up observations. TT Ind, 1H 1933+510 and V2051 Oph would be
promising targets for CCD observers.
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).
*** New Mailing Lists of the Week ***
The following VSNET mailing lists are newly available:
vsnet-ip: Intermediate polar type cataclysmic variables
(IPs, DQ Her stars)
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-ip/msg00001.html
vsnet-campaign-be: Be-stars campaign (including delta Sco!)
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-campaign-be/msg00001.html
vsnet-campaign-ip: Intermediate polar campaign
(mainly pulse timing observation)
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-campaign-ip/msg00001.html
vsnet-campaign-image: Graphical representation of VSNET campaign
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-campaign-image/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-sequence your e-mail address
SUBSCRIBE vsnet-const 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. 24, 2000, as VSNET campaign circulation 389.
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
Delta Sco (RA = 16h00m19s.9, Dec = -22d37'17")
S. Otero discovered that the bright B0.5IV star Delta Sco is
probably brighter than the normal. He pointed out that, in the published
photometric data, there is one isolate observation at 2.21mag in the
normal 2.31 - 2.33mag. He suggested it is a possible gamma Cas (GCAS)
variable (active Be stars). (vsnet-be 2). The spectroscopic confirmation
that it is a new GCAS star, was reported in [vsnet-be 3] and IAUC 7461.
Spectra taken with the 1.3m telescope at Skinakas Observatory (Crete, Greece)
on July 19 revealed the H-alpha line in emission. The bright star
delta Scorpii is currently undergoing a major optical and H-alpha outburst
(vsnet-campaign-be 2). S. Otero reported the additional observations and
estimated the rate of brightening to be +- 0.02 mag. per day
(vsnet-campaign-be 4).
Delta Sco has now become one of the brightest GCAS stars among
historically recorded outbursts of this class. Please watch closely and
report your observations.
V4641 Sgr (RA = 18h19m21s.6, Dec = -25d24'25")
An extreme fast X-ray nova, V4641 Sgr, which experienced a giant
outburst in 1999 September, was reported to show a renewed activity,
possibly mini-outburst, in X-ray and radio range (vsnet-campaign-xray 9).
R. Hjellming noticed to T. Kato and he forwarded that on early July 17
they detected it as a 1.6 mJy source at 8.4 GHZ and the source had resumed
optical activity a week ago (vsnet-campaign-xray 11). Through the optical
observation at Kyoto on July 18, it was confirmed that the object seems
to be calm at 13.39mag (vsnet-campaign-xray 15). R. Hjellming reported
that it is close to a constant source of about 1.2 mJy within the error bars.
So, while V4641 Sgr has returned to producing a radio source, it is
definitely not a short time scale radio event (vsnet-campaign-xray 20).
It experienced very short outburst. Keep close monitorings.
S5 0716+714 (RA = 07h21m53s.4, Dec = 71d20'36")
The blazer S5-0716+71 was reported to be slightly brighter at 14.2mag
on July 16 (vsnet-campaign-blazer 33).
SN 2000cx (RA = 01h24m46s.15, Dec = +09o30'30".9)
The LOSS KAIT team has discovered a bright supernova in NGC 524.
The SN was discovered and confirmed on July 17.5 (mag about 14.5) and
Jul 18.4 (mag about 14.3), respectively. The position is 23".0 west and
109".3 south of the nucleus of NGC 524 (vsnet-campaign-sn 15).
H. Yamaoka commented that the type of the host galaxy (S0) and the
reported magnitudes suggest that it was of type Ia just before maximum
which can be estimated around mag 14 (vsnet-campaign-sn 16).
R. Modic reported the observation to [vsnet-obs 28691] that it was bright
at about 13.6mag on July 20 (vsnet-campaign-sn 18). Weidong Li commented
that it was too bright for its recession velocity and getting a spectrum to
check whether it is SN 1991T-like is interesting, since the host galaxy is
of type S0 but looks very much like an Elliptical, and no SN 1991T-like Ia
has been found in E galaxies yet (vsnet-campaign-sn 23). And then,
commented by H. Yamaoka, according to IAUC 7463, the object turned out to
be of a peculiar type Ia SN, like SN 1991T. SN 2000cx is the first-ever
example of bright SNeIa in the early-type galaxy (vsnet-campaign-sn 24).
The follow-up observations of this SN are worthy for the further SN study
for every aspects.
V893 Sco (RA = 16h14m45s.26, Dec = -28d39"30'.3)
As reported by B. Monard and R. Stubbings on 18, 19 July, V893 Sco was
in outburst at the magnitude of 12.6 (vsnet-campaign 379).
The fading was confirmed on July 20 at 13.8mag by R. Stubbings
(vsnet-campaign-dn 50). This dwarf nova below the period gap again
showed a normal outburst. Now it is in quiescence.
V792 Cyg (RA = 19h31m00s.50, Dec = +33d47'11".8)
This dwarf nova was reported to be undergoing a bright outburst
(13.7mag on July 19 by S. O'Connor). It was the brightest outburst
ever reported to VSNET (vsnet-campaign 380).
Observations are encouraged.
1H 1933+510 (RA = 19h34m36s.08, Dec = +51d07'42".2)
C. Bryja reported that this nova-like variable (=Cyg2 in the Downes
& Shara catalogue 1987, PASP) to be more than three magnitudes high on
July 23.
Close monitorings or time-series photometry will be useful to study
the nature of this brightening.
V2051 Oph (RA = 17h08m19s.1, Dec = -25d48'31".1)
As reported by P. Williams on July 22, this eclipsing SU UMa type dwarf
nova occurred a outburst (likely normal) (vsnet-campaign 387).
Now it is in outburst (neat end of outburst?), time-series observations
including eclipses are urged.
TT Ind (RA = 20h33m39s.79, Dec = -56d33'43".8)
The observation by R. Stubbings showed a relatively rare outburst of
this dwarf nova (13.8mag on July 23). The last outburst occurred in 2000
March. The 1999 December outburst looks like a superoutburst
(vsnet-campaign 388).
Time-resolved photometry during long, bright outburst is encouraged.
(continuous targets)
V1494 Aql (RA = 19h23m05s.4, Dec = +04d57'20".1)
A. Retter reported the main results through 14 nights observations by
R. Novak and L. Cook: there is a very strong signal at 14.86 c/d=1.62 h.
It is near a 1-d alias of the periodicity previously reported to the IAUC.
The full amplitude was slightly increased and was nearly 0.10 mag.
There might be other periodicities, however, to establish their presence,
more data is needed (vsnet-campaign-nova 52).
V446 Her (RA = 18h57m21s.51, Dec = +13d14'27".3)
E. Pavlenko reported an outburst of V446 Her whose international
campaign is currently undergoing conducted by B. Gaensicke et al.
(see "future schedule" or [vsnet-campaign 325, 368]) (vsnet-campaign 378).
E. Pavlenko again reported a possible outburst at 15.46mag on July 21
(vsnet-campaign 381). D. Nogami, who is a member of the campaign
conductors, asked observers to make a close monitor of this star to reveal
the whole shape of this outburst, and noticed that time resolved photometry
is not necessary, but occasional imaging, say, each 2-3 hours, is enough
(vsnet-campaign 382).
AW Sge (RA = 19h58m37s.11, Dec = +16d41'28".8)
A rapid fading trend was confirmed during July 18 - 19
(vsnet-campaign-dn 44).
Now it is near at quiescence. Keep close monitorings to catch
possible rebrightenings.
DM Lyr (RA = 18h58m45s.02, Dec = +30d15'39".9)
A rapid fading trend was confirmed on July 18, but the duration of
the outburst may be somewhat short, which possibly suggested a
rebrightening (vsnet-campaign-dn 46).
V1141 Aql (RA = 19h37m10s.01, Dec = +02d35'59".2)
The object has faded from the last week outburst ( <15.0mag on July 23).
V844 Her (RA = 16h25m01s.69, Dec = +39d09'25".9)
The superoutburst is now ongoing. The current magnitude is about
12.7mag. Time-series observations are strongly encouraged.
QW Ser (RA = 15h26m13s.99, Dec = +08d18'03".8)
M. Richmond reported his new run and the URL of his results
(see "General Information") (vsnet-campaign-data 24).
The superoutburst has entered the rapid fading stage on July 20
at 14.5mag by A. Pearce (vsnet-campaign-dn 51).
The international VSNET campaign conducted by R. Novak is ongoing,
and more observations at this stage are very important to study the
development of late superhumps and possible rebrightenings.
MKN421 (RA = 11h04m27s, Dec = +38d12'32")
The fading trend was interrupted around July 20 (vsnet-campaign-blazer 39)
and has turned into recovery (13.4mag on July 21) (vsnet-campaign-blazer 42).
CI Aql (RA = 18h52m03s.6, Dec = -01d28m38.9s)
This nova keeps a linear fading. There was a slight hint of a secondary
eclipse in July 18 data observed at Kyoto (vsnet-campaign-nova 55).
An egress from the primary minimum was observed in July 19 Kyoto data
(vsnet-campaign-nova 58). An ingress to the primary minimum was observed
in the July 20 run (vsnet-campaign-nova 61).
For detailed eclipse analysis, multi-longitude observations are
encouraged.
V803 Cen (RA = 13h23m44s.5, Dec = -41d44'30".1)
The strong oscillation has been continued. The fading to 14.8mag on
July 19 and the recovery to 13.6mag on July 23 were observed
(vsnet-campaign-dn 58).
We should keep close monitorings.
BL Lac (RA = 22h02m42s.86, Dec = +42d16'37.6")
The object was slightly fainter on 19 July (15.1 or 15.2mag)
(vsnet-campaign-blazer 36), and keep the magnitude till July 22 when
it dropped to 15.4mag (vsnet-campaign-blazer 43).
XTE J1118+480 (RA = 11h18m10s.9, Dec = +48d02'12".9)
From the last week observation at Kyoto, the fading trend has become
more apparent (vsnet-campaign-xray 14). Within the last two weeks,
the object has become about 0.3mag fainter. The light curve observed
on July 18 is covered about three hours under good condition, but no
prominent humps were detected.
The object may change its physical state during this rapid decline phase.
More observations are urged.
*** 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).
In [vsnet-campaign 368].....
"The V446 Her campaign from July 7 was started (through the end of
September). But we have received very few observations since then.
Negative observations, for instance, <17.0, are also useful.
We strongly encourage observers to contribute to this project.
Let's clarify the physics of post novae!"
*** General information ***
QW Ser
The light curves, charts, and data by M. Richmond can be seen at:
http://a188-L009.rit.edu/richmond/qwser/qwser.html
http://a188-L009.rit.edu/richmond/qwser/jul7_qwser.dat
[vsnet-campaign-data 24]
V893 Sco
eclipse ephemeris, see [vsnet-campaign 379]
V2051 Oph
eclipse ephemeris, see [vsnet-campaign 387]
We have set up a new list, vsnet-campaign-be. The new list
is totally devoted to dedicated campaigns of dramatic Be star phenomena.
[vsnet-campaign-be 1]
We have set up a new list, vsnet-campaign-ip. The new list
is totally devoted to dedicated campaigns of intermediate polars (IPs).
[vsnet-campaign-ip 1]
(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