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[vsnet-campaign-news 107] News from VSNET 78
*** News from VSNET ***
T. Vanmunster revealed that SDSSp J173008.38+624754.7 is a new
member of SU UMa-type dwarf novae currently in a superoutburst.
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 October 29, 2001, as VSNET campaign circulation 1201
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
AM Cas (RA = 02h26m23s.40, Dec = +71d18'32".3)
T. Kato reported that during the past one month, the outburst
cycle length and amplitude of AM Cas have decreased. This
behavior resemble the behavior in some Z Cam stars just before
entering standstills. Since the existence of standstills has not
been very clearly demonstrated in AM Cas, SS Cyg-type star with
the shortest outburst cycle length (cf. Kato et al. 2001, MNRAS
in press), further detailed observations to follow the consequence
of the present behavior are strongly encouraged (vsnet-campaign 1199).
Possible Nova in SMC (RA = 00h46m27s.8, Dec = -73d29'40".1)
B. Liller discovered a possible nova in SMC in the photographs
taken at October 21.0857 and Oct. 21.0879. The magnitude was 12.1
mag on the photographs and no object brighter than 13.5 was seen
before September 27 (vsnet-campaign-nova 635, 636). The object
rapidly faded around October 23 and 24 (vsnet-campaign-nova 639,
641), and now the decline rate becomes more gradual. The current
magnitude is about 13.7mag (vsnet-campaign-nova 647).
SN 2001fb (RA = 00h10m06s.15, Dec = -00d26'18".2)
IAUC 7740 tells that A. Rest reported the detection of an apparent
supernova (at magnitudes g' = 20.0, r' = 19.0) on SDSS images taken
on October 10.3. H. Yamaoka reported that the host galaxy of
SN 2001fb is UM 207 = SDSS J001006.63-002609.5, whose recession
velocity is measured as 9648 km/s. The expected maximum for typical
SN Ia is thus around mag 17 (vsnet-campaign-sn 269).
V1504 Cyg (RA = 19h28m55.87s, Dec = +43d05'39".9)
As reported by M. Simonsen on October 21, an outburst of
V1504 Cyg were detected at 14.6mag. It may be a superoutburst
(vsnet-campaign-dn 1764).
DH Aql (RA = 19h26m12s.05, Dec = -10d15'21".4)
As reported by Pavol A. Dubovsky on October 20, an outburst of
DH Aql were detected at 13.0mag. It may be a superoutbust
(vsnet-campaign-dn 1765).
TV Col (RA = 05h29m25s.5, Dec = -32d49'05".2)
As reported by B. Monard on October 23, an outburst of TV Col
was detected at 13.3mag (vsnet-campaign-ip 64).
DI UMa (RA = 09h12m22s.16, Dec = +50d49'39".1)
T. Kinnunen reported an outburst reaching 15.4mag on October 23
(vsnet-campaign-dn 1176).
AM Her (RA = 18h16m13s.4, Dec = +49d52'03".1)
The polar prototype AM Her has started fading as reported
by M. Verdenet (14.2mag) on October 25 (vsnet-campaign 1198).
The fading continues and the current magnitude is about 14.2mag
(vsnet-campaign 1200).
U Gem (RA = 07h55m05s.55, Dec = +22d00'09".2)
An outburst reaching 12.6mag was detected by M. Simonsen
on October 28 (vsnet-campaign-dn 1794).
(continuous targets)
SN 2001el (RA = 03h44m30s.57, Dec = -44d38'23".7)
This supernova started fading since the last week. It is
now probably fainter than 13.5mag (vsnet-campaign-sn 267).
SDSSp J173008.38+624754.7 (RA = 17h30m08s.38, Dec = +62d47'54".7)
On October 22, T. Vanmunster reported his detection of superhumps
which revealed this object to be an SU UMa-type dwarf nova. He
performed time-series photometry on October 19/20 and detected a
part of a hump. His run on October 22/23 clearly showed a typical
superhump profile whose amplitude was about 0.40mag and period was
reported to be 0.0801(9) days, relatively long period in SU UMa stars
(vsnet-campaign-dn 1758, vsnet-campaign 1196, vsnet-campaign-dn 1760,
vsnet-campaign-dn 1763, vsnet-campaign-dn 1772). The Nyrola and
Kyoto team confirmed the humps (vsnet-campaign 1195, vsnet-campaign-dn
1759). T. Kato reported there was some evidence of superimposed QPOs
with a period of ~10 min (vsnet-campaign-dn 1768, 1769, 1781).
The VSNET collaboration team has received the data from the Kyoto
team, T. Vanmunster, and the Nyrola team. The combined data shows
a periodicity of 0.079294(34) d and possible period shortening
(vsnet-campaign-dn 1779, 1781, 1786, 1790, 1792). The object
gradually faded with a rate of 0.13mag/d (vsnet-campaign-dn 1790).
The superoutburst is still ongoing (vsnet-campaign-dn 1770, 1774,
1777, 1783, 1795).
IP Peg (RA = 23h23m08s.7, Dec = +18d24'59".1)
The object started fading from the outburst since the end of the
last week (vsnet-campaign-dn 1766, 1775, 1784, 1788).
Nova Cen 2001 (RA = 13h55m41s.27, Dec = -64d15'57".9)
The reported magnitudes showed strong oscillations around 11.1mag
(vsnet-campaign-nova 637) until around October 22, and then, it
brightened to the second maximum of 10.4mag on October 23 as
reported by A. Pearce (vsnet-campaign-nova 638, 640). The object
is fading from the second maximum. It is now at about 11.6mag
(vsnet-campaign-nova 644, 646).
SN 2001ep (RA = 04h57m00s.26, Dec = -04d45'40".2)
H. Yamaoka reported that IAUC 7731 (Oct. 10) tells that SN 2001ep
is of type Ia near maximum. Recent observation shows that it seems
to be a normal one (vsnet-campaign-sn 268).
MV Lyr (RA = 19h07m15s.93, Dec = +44d01'10".7)
It is steady at about 13.4mag (vsnet-campaign-nl 49).
EF Peg (RA = 21h15m04s, Dec = +14d03'50")
The object seems to start a rapid fading from the superoutburst
on October 20 as reported by Pavol A. Dubovsky (vsnet-campaign-dn
1762). M. Uemura performed period analysis using the data sets
by the VSNET collaboration team (the Kyoto team, D. Starkey, and
J. Pietz) and reported a period of 0.086509 (24) d. Early phase
observations by D. Starkey showed a short period or double-peak
profile of humps. The later phase data yields a slightly longer
period of 0.086686 (34) d (vsnet-campaign-dn 1171). After the
rapid decline phase, observations by the Kyoto team detected a
possible rebrightening on October 24 (vsnet-campaign-dn 1791).
It is now at post-superoutburst phase (vsnet-campaign-dn 1785).
V4740 Sgr (RA = 18h11m45s.82, Dec = -30d30'49".9)
The smooth fading continues (vsnet-campaign-nova 642, 645).
WZ Sge (RA = 20h07m36s.53, Dec = +17d42'15".3)
The slow fading still continues (vsnet-campaign-dn 1761, 1773,
1782). The VSNET team has received a number of additional data
sets from new collaborators (vsnet-campaign-dn 1767).
The light curve on October 17 shows possible eclipses and humps
at phase near 0.45. The amplitude of the possible variations was
about 0.2mag. The amplitude seems to be smaller on October 19.
We can see possible shallow and wide eclipses. The eclipses precede
the prediction time on October 22. Two possible dips (or humps?)
were seen (vsnet-campaign-dn 1780). The analysis of the Kyoto
Oct. 25 data shows a jump (or eclipse-like fading) at phase 0.2
which has not been recorded in the recent light curves
(vsnet-campaign-dn 1789).
V368 Peg (RA = 22h58m43s.5, Dec = +11d09'13")
I. Andronov reported that observations of 2000 superoutburst of
V368 Peg by them revealed the decrease of the photometric period
with luminosity by a factor of 2.3 times. The more detailed report
is available at http://il-a.pochtamt.ru/V368_Peg.htm
(vsnet-campaign 1197).
*** Future schedule ***
WZ Sge campaign
D. Steeghs wrote:
"Several of us are organizing a campaign on the current outburst
of WZ Sge, using a large variety of ground based facilities as well as
space observatories. A web-page has been setup listing the scheduled
observations so far which we intend to keep up to date at:
http://vsnet.astro.soton.ac.uk/~ds/wzsge.html
"
For more information, see [vsnet-campaign 1039]
Supernova campaign: A great opportunity for amateurs by M. Schwartz.
For more detailed information, see [vsnet-campaign-sn 233]
announce on the HST observations, see [vsnet-campaign-sn 240, 246]
International Conference on Classical Nova Explosions
Sitges (Barcelona), Spain: 20-24 May 2002
For more detailed information, see http://vsnet.ieec.fcr.es/novaconf
[vsnet-campaign-nova 643]
*** General information ***
SDSSp J173008.38+624754.7
CCD image presented by A. Oksanen:
http://vsnet.jklsirius.fi/obs/sdss1730map.jpg
[vsnet-campaign-dn 1778]
Light curve by T. Vanmunster:
http://vsnet.lunarpages.com/cbabelgium
[vsnet-campaign-dn 1787]
U Gem
eclipse ephemeris, see [vsnet-campaign-dn 1793]
(This summary can be cited.)
Regards,
Makoto Uemura
vsnet-adm@kusastro.kyoto-u.ac.jp
Return to Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
VSNET Home Page