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[vsnet-campaign-news 17] News from VSNET 17
*** 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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A naked-eye variable star, rho Cas (normally at around 4.5-5.0 mag)
has still be in the fainter state. In this week, the observations
of 5.0-5.5 mag are reported to VSNET. Close monitorings will play
an important role to study the nature of this activity.
Several interesting findings about dwarf novae are reported.
V405 Vul, which was an SU UMa-type dwarf nova candidate, experienced
an new outburst. T. Vanmunster observed during the outburst and
revealed this object is a genuine SU UMa-star, furthermore, with
the second-longest superhump period. Only TU Men is known to have
a longer superhump period. This object is now a high priority
targets of VSNET campaign. V405 Vul is now near the end of this outburst.
More observations of the early phase are expected in the next outburst.
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).
Or, look at the list information page for more details:
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/information.html
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The following was issued on Aug. 29, 2000, as VSNET campaign circulation 456.
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
NSV 14652 (RA = 23h38m49s.1, Dec = +28d19'55")
As reported by T. Vaunmunster on August 22 in [vsnet-alert 5202],
the suspected dwarf nova NSV 14652, the possible identification with
a ROSAT source, experienced the outburst at 15.8mag (vsnet-campaign 439).
P. Schmeer reported another brightening for a few days in 1993 June
(vsnet-campaign 439). T. Vanmunster performed a time-series observation
on August 22/23 which yielded a 0.5 mag modulation in the resulting
light curve (covering a total of 6.1 hours) (vsnet-campaign 443).
The confirmation of modulation and the current state is needed.
V425 Cas (RA = 23h03m38s.60, Dec = +53d17'10".8)
The VY Scl-type novalike system V425 Cas may be in faint state (15.1mag
on August 21 by T. Kinnunen). The object was in "high" state in 1999,
but experienced a low state in 1998 (vsnet-campaign 441).
Both deep nightly observations and time-resolved photometry are
recommended.
V368 Peg (RA = 22h58m43s.5, Dec = +11d09'13")
V368 Peg = Var63 Peg started the outburst, as reported by R. Stubbings
(13.8mag on August 26). The star is an SU UMa-type dwarf nova,
whose nature was revealed by J. Pietz (vsnet-obs 22110, vsnet-alert 3317)
during the last outburst in 1999 August (vsnet-campaign 448).
The E. Muyllaert's observations showed the object was bright on August 26
(12.5mag), which strongly suggested the outburst is a superoutburst
(vsnet-campaign 454).
Time-series photometry is strongly encouraged to study the superhump.
LX And (RA = 02h19m44s.00, Dec = +40d27'23".5)
The outburst of this dwarf nova was detected by M. Simonsen on August 12.
T. Vanmunster performed time-series photometry on August 12/13 and 13/14
and reported that the resulting light curve is more or less flat, with
presumably traces of short term modulations with very low amplitude
(around 0.01 mag) (vsnet-campaign 437).
FX Cep (RA = 21h03m12.5s, Dec = +66d10m51.2s)
T. Kinnunen detected the outburst at 15.0mag on August 23
(vsnet-outburst 415). T. Vanmunster performed a time-series CCD
photometry on August 23/24 and reported the light curve is rather flat.
He suggested that this variable is an UGSS-type dwarf nova
(vsnet-campaign 445).
V1062 Cyg (RA = 21h08m12s.60, Dec = +36d49'16".6)
Recent observations show possible separate outbursts, i.e. 14.6:
on August 21 and 14.6: on August 25 (by M. Simonsen) (vsnet-campaign 450).
Close monitorings and time-series observations are encouraged.
V405 Vul (RA = 19h53m05s.0, Dec = +21d14'50")
T. Vanmunster performed a time-series observations on August 25/26,
and revealed that it clearly shows superhumps with the period of
0.1205 +/- 0.0019 d and a full superhump amplitude of 0.19 mag.
This findings confirmed V405 Vul as an SU UMa dwarf nova with the
second-longest superhump period, and very close to the upper border
of the period gap (vsnet-campaign 452).
This became a high priority target. More observations in early phase of
superoutburst are expected in the next outburst. The confirmation
of the current state is also important.
V1141 Aql (RA = 19h37m10s.01, Dec = +02d35'59".2)
As reported by R. Stubbings, the (still poorly studied) SU UMa-type
dwarf nova V1141 Aql is undergoing an outburst (15.0mag on August 28).
The object was observed in superoutburst in 1999 October, the first
time when superhumps were detected (vsnet-campaign 455).
Time-series observations are strongly encouraged.
(continuous targets)
Rho Cas (RA = 23h54m22s.99, Dec = +57d29'58".7)
T. Kato forwarded the observation by M. Nezel (5.1mag on August 22)
(vsnet-campaign-rhocas 5). The faint state continues. Close
monitorings are encouraged.
V550 Cyg (RA = 20h05m05s.21, Dec = +32d21'21".0)
T. Kato found on August 21 that the real position seems to be slightly
east to the DWS position by comparing the images (in outburst) and available
charts (vsnet-campaign-dn 115). On August 22, Ouda team reported the
revised superhump period of 0.0682 d, or its alias 0.0639 d and that
there is an evidence of super-QPOs around every superhump minimum
(vsnet-campaign 436). J. Pietz provided time-series data which confirms
the presence of superhumps (vsnet-campaign-dn 117). H. Yamaoka
performed astrometry using the images taken at Ouda and reported that
the object observed by O'conner (vsnet-obs 29250) is not the real V550 Cyg,
and the position mentioned on vsnet-campaign 435 (weekly Campaign Summary
by Uemura) is incorrect (the correct coordinate is written above).
And, the real V550 Cyg is about 3" east or east-southeast from the DWS
position and the position of the candidate of V550 Cyg at quiescent (Skiff,
1999, IBVS 4675). Further, on the DSS2 Bj images, the faint object
(19.5-20.0) lies on the neighbour of the position. The amplitude of
this CV is therefore quite large, likely more than 5 magnitude
(vsnet-campaign-dn 120, vsnet-campaign 447).
The final phase of this superoutburst will come within this few days.
Observations are encouraged.
V1504 Cyg (RA = 19h28m55s.87, Dec = +43d05'39".9)
Relatively bright outburst (14.2mag) was detected by L. Cook on
August 26 (vsnet-campaign 449).
Delta Sco (RA = 16h00m19s.9, Dec = -22d37'17")
The object is still brighter than the normal state.
Close monitorings are encouraged.
SN 2000cx (RA = 01h24m46s.15, Dec = +09o30'30".9)
The object showed a relatively rapid fading in the last week
(vsnet-campaign-sn 54).
XTE J1118+480 (RA = 11h18m10s.9, Dec = +48d02'12".9)
M. Uemura reported a possible rebrightening from the rapid decline
on August 22 from the recent Kyoto observations (vsnet-campaign-xray 41),
however, no prominent rebrightening is confirmed from the data on August 23.
The decline trend has become more gradual (vsnet-campaign-xray 42).
Nyrola team performed a time-series photometry on August 24 and reported
that the data shows 0.5 magnitude variability that is about twice the
measurement error and the average magnitude to be 17.03mag
(vsnet-campaign-xray 43).
The object is now faint, but still brighter than the quiescent state.
Observations are encouraged.
V803 Cen (RA = 13h23m44.5s, Dec = -41d44'30".1)
The brightness of this object again showed an oscillation from 14.2mag
on August 17.419 to 13.4mag on August 20.456 reported by R. Stubbings
(vsnet-campaign-dn 114). The fading from this outburst was observed
on August 22 by R. Stubbings (vsnet-campaign-dn 119), and then,
again enter the fainter state on August 26 (14.6mag by R. Stubbings).
NSV 26158 (RA = 23h53m51.02s and Dec = +23d09'19.5")
The unclassified brightening continues during the last week
(vsnet-campaign 442). T. Kinnunen reported the fading from this
brightening on August 23 (15.2mag) - 25 (15.5mag) (vsnet-campaign 451).
Multicolor photometry and spectroscopy are encouraged to monitor
the change in the object's status.
V446 Her (RA = 18h57m21s.51, Dec = +13d14'27".3)
D. Nogami reported a preliminary results of V446 Her campaign scheduled
throughout this summer. The light curve is peculiar for a dwarf nova.
See below for more detail information (vsnet-campaign 446).
*** Future schedule ***
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 446].....
"Now, one and a half month later, we present a preliminary lightcurve
which you can find at
"http://alpha.uni-sw.gwdg.de/~mschrei/v446her/light.gif".
The light curve is very interesting, ......
Hence we again invite those of you equipped with a CCD camera to
obtain a couple of images of V446Her per night at least until the
end of September. Together we can rewrite the post nova scenario !!!"
*** General information ***
P Cyg
E. Pollmann presents the development of the Halpha-emission of P Cyg
after the minimum at JD 2451770, see [vsnet-campaign-image 3] or
[vsnet-campaign 444].
V446 Her
Preliminary light curve from V446 Her campaign team:
http://alpha.uni-sw.gwdg.de/~mschrei/v446her/light.gif
[vsnet-campaign 446]
(This summary is reproduction free.)
Regards,
Makoto Uemura
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VSNET Home Page: http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/
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