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[vsnet-campaign-news 50] News from VSNET 50
*** News from VSNET ***
The SU UMa type dwarf nova IX Dra is undergoing a superoutburst.
The activity seems to confirm its very short recurrence period.
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 Apr. 16, 2001, as VSNET campaign circulation 860.
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
IX Dra (RA = 18h12m32s.2, Dec = +67d04'41")
R. Ishioka, the Kyoto team, reported an outburst (~15mag) of
IX Dra on April 13 (vsnet-campaign 851). The light curve shows
clear superhumps with a period of 0.068 d. Combined with previous
observations, this seem to confirm our previous suggestion as a
new ER UMa star (vsnet-alert 5370) or a closely related system
(vsnet-campaign 854). An additional run on April 14 and 15 also shows
superhumps, and the combined data show 0.6697 d period
(vsnet-campaign-dn 653, 665).
V436 Cen (RA = 11h13m58.2s, Dec = -37d40'45".0)
V436 Cen, the SU UMa-type dwarf nova with a short orbital period,
is undergoing a relatively bright outburst as reported by R. Stubbings
on April 12 (11.8mag). The last reported superoutburst of V436 Cen
occurred in 2000 June (vsnet-campaign 848, vsnet-campaign-dn 643).
The outburst continues (vsnet-campaign-dn 660).
AK Cnc (RA = 08h55m18s.49, Dec = +11d18'06".2)
The short period SU UMa star AK Cnc experienced an outburst at
13.4mag as reported by R. Stubbings on April 12 (vsnet-campaign 849,
vsnet-campaign-dn 644). The outburst continues (vsnet-campaign-dn 648,
658).
BV Cen (RA = 13h31m19s.6, Dec = -54d58'34")
BV Cen is undergoing an outburst. The last major outburst of BV Cen
occurred in 2000 May (vsnet-campaign 850). The current magnitude
is about 12.2mag (vsnet-campaign-dn 642).
V383 Vel (RA = 10h21m41s.7, Dec = -49d49'24".33")
As reported by B. Monard on April 10, this dwarf nova experienced
an outburst at 14.2mag. This star seems to have a relatively steady
outburst interval of ~2 months (vsnet-campaign-dn 634). Since April
11, it has rapidly faded (vsnet-campaign-dn 637).
ST Cha (RA = 10h47m31s.3, Dec = -79d27'17")
The cataclysmic variable ST Cha has faded to <15.0mag since April 12.
The object had stayed at around mag 14 since this February
(just like a standstill). The object had much larger variations,
more or less resembling outbursts, before that time.
GK Per (RA = 03h31m12s.50, Dec = +43d54'17".8)
M. Simonsen reported that the intermediate polar (and also an old nova)
GK Per is brighter than usual (12.7mag on April 14) (vsnet-campaign-ip 47).
P. Schmeer reported 12.8mag on April 12 (vsnet-campaign-ip 49).
The slightly bright state continues (vsnet-campaign-ip 48, 50).
CT Hya (RA = 08h51m04s.50, Dec = +03d07'43".5)
M. Simonsen reported a bright outburst of the SU UMa-type dwarf nova,
CT Hya on April 14. A well-observed superoutburst occurred in 2000
November-December. The present epoch may be too premature for another
superoutburst, but the present brightness (13.9mag) is comparable
to those of superoutbursts. The next observations show a rapid fading
or no outburst (vsnet-campaign-dn 662).
EI UMa (RA = 08h38m22s.1, Dec = +48d38'01")
The NL-type cataclysmic variable EI UMa is reported active between
13.6 - 14.7 (vsnet-campaign-nl 11).
omega CMa (RA = 07h14m48s.6, Dec = -26d46'22")
Omega CMa was reported bright (3.9mag by S. Otero; vsnet-campaign-be 98).
RX J1155.4-5641 (RA = 11h55m27.6s, Dec = -56d41'48")
The ROSAT-selected dwarf nova RX J1155.4-5641 is in outburst (12.5mag),
as reported by B. Monard. This object shows two types of outbursts
(long and short), a long one occurring in 2001 January
(vsnet-campaign-dn 657).
DI UMa (RA = 09h12m22s.16, Dec = +50d49'39".1)
Recent outburst observations of DI UMa by M. Reszelski indicate
that detectable outbursts of DI UMa comes every 24-31 days.
If the detected outbursts are superoutbursts, this observed interval
is pretty close to the 22-d value (vsnet-alert 374). If this is confirmed,
the system may have returned to the state originally qualified DI UMa
as the "most extremely RZ LMi-like object", the extreme end of ER UMa
stars (vsnet-campaign 858).
New CVs from 2QZ survey
The following new CVs are listed in the recently released 2QZ
survey. Any outburst of these objects is a TOO target for the VSNET
Collaboration team.
2QZ_J010946.1-274524 010946.16 -274524.7 star(CV) B=19.86
2QZ_J121005.3-025543 121005.30 -025543.9 star(CV) B=20.72
2QZ_J140321.8-014651 140321.87 -014651.3 star(CV)? B=20.51
2QZ_J142256.3-022108 142256.32 -022108.7 star(CV) B=19.54
2QZ_J142438.9-022739 142438.94 -022739.9 star(CV) B=19.52
2QZ_J221856.4-281618 221856.47 -281618.7 star(CV) B=20.82
2QZ_J235703.1-314911 235703.17 -314911.3 star(CV) B=20.41
(continuous targets)
TU Crt (RA = 11h03m36s.50, Dec = -21d37'45".6)
The superoutburst continues (vsnet-campaign-dn 633, 641, 651, 654, 659).
R. Ishioka reported that the Kyoto team performed a time-series
observation on April 10 (vsnet-campaign 841). The light curve
shows fully grown superhumps with an amplitude of 0.3mag
(vsnet-campaign-dn 635).
VV Pup (RA = 08h15m06s.73, Dec = -19d03'16".8)
The analysis of the Kyoto optical observation (by Ishioka-san),
quasi-simultaneous with the FUSE observation, shows sharp and giant
hump (15.24 - 17.7 mag). This observation indicate that VV Pup
is in actively accreting state (vsnet-campaign 844, 845).
V485 Cen (RA = 12h57m23s.30, Dec = -33d12'06".8)
T. Kato reported that the analysis of the early part of the Kyoto
data and M. Bos's data sent by A. Retter clearly shows the presence
of superhumps. The object has shown monotonous fading during this period.
The average superhump period is 0.04209 d, which is slightly shorter
than the previous report by Olech (Acta Astrion. 47, 281)
(vsnet-campaign-dn 636, 638, 639). After the superoutburst terminated,
a possible re-brightening was reported by the Kyoto team
(vsnet-campaign 856).
Delta Sco (RA = 16h00m19s.9, Dec = -22d37'17")
The bright state continues (vsnet-campaign-be 97, 99).
V803 Cen (RA = 13h23m44.5s, Dec = -41d44'30".1)
The oscillation between 14.5 - 13.7 still continues
(vsnet-campaign-dn 645).
MKN 421 (RA = 11h04m27s, Dec = +38d12'32")
12.7 - 13.1 mag were reported during the last week
(vsnet-campaign-blazar 178).
3C 279 (RA = 12h56m11s.1, Dec = -05d47'20")
The slightly bright state continues (vsnet-campaign-blazar 177).
U Gem (RA = 07h55m05s.55, Dec = +22d00'09".2)
The slightly active state continues (vsnet-campaign-dn 646).
CR Boo (RA = 13h48m55s.42, Dec = +07d57'30".3)
As reported by M. Simonsen, CR Boo has experienced an outburst
since April 14 (vsnet-campaign-dn 649). The outburst continues
(vsnet-campaign-dn 656, 663).
DW Cnc (RA = 07h58m56s.80, Dec = +16d16'48".2)
Some observations show the object became fainter than 14.5mag
(vsnet-campaign-dn 650, 661). R. Novak's data shows strong modulations
with a period of 0.029 d, which is the shorter one of the previously
reported two dominant periods (vsnet-campaign-dn 655).
SN 2001V (RA = 11h57m24s.93, Dec = +25d12'09".0)
The fading continues and the current magnitude is about 16C
(vsnet-campaign-sn 170).
V445 Pup (RA = 07h37m56s.88, Dec = -25d56'59".1)
The gradual fading continues, and the current magnitude is about
10.4mag (vsnet-campaign-nova 279).
CI Aql (RA = 18h52m03.6s, Dec = -01d28m38.9s)
The object is gradually faded, and the current magnitude is
about 14.7mag (vsnet-campaign-nova 280).
*** Future schedule ***
CR Boo and V803 Cen campaign conducted by J. Patterson
in [vsnet-campaign-dn 640 and vsnet-campaign 852]
"We have started a photometry campaign on the helium dwarf novae CR
Boo and V803 Cen, designed mostly to trace the extremely rapid up-and-down
excursions of these stars. Right now both stars are in "cycling states",
in which they go back and forth between about 13.4 and 14.6, with a period
somewhere in the range 18-24 hours. Naturally this is a really awkward
period to study, unless you have observers spread around at various
longitudes. Also, the nature of this variation is still not known; it
could be just a spectacularly short dwarf-nova recurrence period, or some
(other) kind of disk oscillation not yet found among the more familiar
hydrogen-rich CVs. For these reasons, we eagerly seek observations of
these two fascinating helium stars over the course of our campaigns (about
3 more weeks)."
RZ LMi campaign conducted by J. Patterson on April 2001
For more information, see [vsnet-campaign 718, vsnet-campaign-dn 429].
Elizabeth and Frederick White Workshop
AGN variability across the Electromagnetic Spectrum
25 - 29 June 2001 Sydney, Australia
For more information, see [vsnet-campaign-blazar 168].
Two Years of Science with Chandra *
* This meeting will also be the 12th Annual Maryland Astrophysics
Conference
September 5-7, 2001
For more information, see [vsnet-campaign-xray 66]
*** General information ***
IY UMa
A. Oksanen, Nyrola team, reported a new eclipse ephemeris using
additional data sets on April 4 and 7, see [vsnet-campaign 843]
VV Pup
Hump timing prediction, see [vsnet-campaign 846]
DW Cnc
R. Novak's data sets are available via Amateur Data Archvie
(http://ada.astronomy.cz).
[vsnet-campaign-dn 652]
U Gem
eclipse ephemeris, see [vsnet-campaign-dn 664]
CI Aql
eclipse ephemeris, see [vsnet-campaign-nova 281]
(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