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[vsnet-campaign-news 35] News from VSNET 35
*** News from VSNET ***
Kazuyoshi Kanatsu (Matsue, Shimane, Japan) reported a bright possible
nova in Puppis. The nature of this new object has not been made clear.
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 Jan. 2, 2001, as VSNET campaign circulation 644.
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
Possible Nova in Pup (RA = 07h37m56s.91, Dec = -25d56'59".7)
Kazuyoshi Kanatsu (Matsue, Shimane, Japan) reported the discovery
of a new variable star, which is likely a nova based on the absence
of apparent counterparts on his previous image, DSS and 2MASS.
His discovery magnitude is mag 8.7p on December 22. K. Takamizawa
(Nagano, Japan) reported prediscovery observations (November 28, 8.6p mag)
on his patrol films. Takamizawa reported that the object was not recorded
on 22 films (limiting magnitude 14) between 1994 March 14 and 1999
December 3. He further reported the presence of a close companion of
14.5 mag USNO star(vsnet-campaign-nova 94). This USNO star is recorded
by 2MASS survey, which gives J=12.50, H=11.75, Ks=11.51, not particularly
red among neibouring stars. K. Takamizawa performed photometry of this
companion star (vsnet-campaign-nova 101). H. Abe performed astrometry
and determined above position of the possible nova (vsnet-alert 5492).
This position agrees that of the USNO star within 1-2 arcsec.
If this star is indeed the progenitor of the erupting object, the color
from the comparison between the visual and 2MASS magnitudes becomes
V-J = +2. The color is not particularly red in this field. Even assuming
that the object is not significantly reddened, the color is still bluer
than most of symbiotic stars, which have V-J colors of +3 to +5 or even
larger. If the object is a nova, the color suggests either a) usual
cataclysmic variable with moderate reddening or b) cataclysmic-type binary
with a relatively evolved secondary (vsnet-campaign-nova 104).
UV Gem (RA = 06h38m44s.51, Dec = +18d16'05".6)
R. Stubbings reported that the SU UMa-type dwarf nova UV Gem is
in outburst at 15.0 on December 27. Even outburst at this magnitude
can be a superoutburst (as in 1999 December one)(vsnet-campaign 628).
The observed magnitude of 15.1mag on December 28 indicates no significant
fading (vsnet-campaign-dn 362).
TT Ind (RA = 20h33m39s.79, Dec = -56d33'43".8)
As reported by R. Stubbings on December 27, TT Ind is in outburst
at 13.5mag (vsnet-campaign 629). The object became brighter (13.0mag)
on December 28 as reported by R. Stubbings (vsnet-campaign-dn 361).
(continuous targets)
RZ Leo (RA = 11h37m22s.27, Dec = +01d48'58".9)
From the observation on December 25 by the Kyoto team and S. Kiyota,
T. Kato reported the superhumps with narrower peaks and with an amplitude
of 0.35 mag (vsnet-campaign 623). A light curve observed by G. Masi
shows one "early superhump" maximum on December 22 (vsnet-campaign 624).
The data until December 26 by the Kyoto team, S. Kiyota, and R. Novak,
yielded a superhump period of 0.07851 d, which is slightly shorter than
the previous determination. This may suggest a shortening of the
superhump period. In the light curve on December 26, superhumps have
become narrower, more resembling those of usual SU UMa type stars.
Secondary superhump maxima (small notches) were visible both on Tsukuba
and Kyoto data (vsnet-campaign 626). An analysis of RZ Leo observations
obtained by T. Vanmunster combined with data supplied by J. Pietz,
revealed a fairly simple superhump signal at 0.0785 +- 0.0002 d.
This yields a fractional period excess of 3.3%, which is a rather standard
excess value (vsnet-campaign 630). From a steep fading seen in December
27 data by the Kyoto team and S. Kiyota, T. Kato suggested there seems to be
a wavy pattern with a period of 2-3 d in the averaged light curve.
This is likely caused by the beat phenomenon between the superhump period
and the orbital period, a natural consequence of a high-inclination system
(vsnet-campaign 633). A brightening which was seen in the Kyoto team
data on December 28 is consistent with the presence of the beat
phenomenon (vsnet-campaign 637). The analysis of all VSNET collaboration
data since December 23.5 UT up to the Kyoto December 29 full run has
yielded the best superhump period of 0.07863 d (vsnet-campaign 640).
J. Pietz presented two light curves at his web site (see below "General
Information"; vsnet-campaign-dn 354). A. Oksanen provided the data on
December 27 and 28 at [vsnet-campaign 634]. The superoutburst is now
ongoing.
WY Tri (RA = 02h25m12s.08, Dec = +33d00'31".5)
M. Uemura (Kyoto team) reported a rapid fading of WY Tri on December 27.
The first confirmed superoutburst was terminated (vsnet-campaign-dn 368).
Observations by the Kyoto team and R. Novak yielded the best candidate of
the superhump period to be 0.078483 day(vsnet-campaign-dn 376).
J. Pieatz presented light curves at his web site (see "General Information";
vsnet-campaign 641).
UV Per (RA = 02h10m13s.58, Dec = +57d11'26".8)
From the observation on December 25 at Kyoto, T. Kato reported
the detection of growing superhumps whose amplitude grew from
less than 0.1 mag to 0.15 mag, and relatively rapid fading (0.3 mag/d).
The superhump period was somewhat longer than that obtained by other
authors on earlier superoutbursts. This suggests that the superhump
was still is in its unsteady phase. It is also striking to note such
an early appearance of superhumps in such a short period system
(vsnet-campaign 622). The Kyoto data on December 26 shows that UV Per
had risen by ~0.5 mag compared to December 25. Fully grown superhumps,
with amplitudes nearly 0.4 mag, were seen (vsnet-campaign 627).
The Kyoto data on December 27 show smooth superhumps with an amplitude
of 0.25 mag, and the rising stopped, and the object is apparently at
maximum (vsnet-campaign 632). The object has been steadily fading
since December 28. Clear superhumps with an amplitude of 0.2 mag are
present in the light curve on December 28 (vsnet-campaign 636).
T. Kato reported the analysis of combined data with Kyoto and B. Martin's
observations, the best superhump period is determined as 0.06661 d
(after the evolution of full superhumps), which is slightly longer than
the previously published period (vsnet-campaign 639). The object
showed somewhat rapid fading on December 29 (vsnet-campaign-dn 371, 372).
J. Pietz presented a light curve at his web site (see "General Information";
vsnet-campaign 641). T. Kato presented a light curve obtained by
VSNET collaboration team at vsnet ftp site (see "General Information";
vsnet-campaign 642). The superoutburst is now ongoing.
BL Lac (RA = 22h02m42.86s, Dec = +42d16'37.6")
The observation reported by T. Kinnunen showed temporary fading (14.8mag)
on December 27 (vsnet-campaign-blazar 121).
TV Col (RA = 05h29m25s.5, Dec = -32d49'05".2)
Following the last outburst on December 24, no major outburst is not
observed on December 25 and 26 (vsnet-campaign-ip 23).
OJ 287 (RA = 08h51m57s, Dec = 20d17'59")
The bright state continues. The current magnitude is about 14.4
(vsnet-campaign-blazar 120).
3C 66A (RA = 02h22m39s.6, Dec = +43d02'08")
The object further brightened to 14.0mag on December 28 as reported by
M. Simonsen (vsnet-campaign-blazar 119).
Delta Sco (RA = 16h00m19s.9, Dec = -22d37'17")
Some observations confirmed Delta Sco is still bright
(vsnet-campaign-be 72, 73).
*** Future schedule ***
TV Col campaign conducted by A. Retter (2001 January 2 - 15):
"Recently using previously published data, we discovered evidence for
another periodicity in the light curve of TV Col. The 6.4-h period would
be the longest recorded positive superhump. To confirm this period, I'll
carry out continuous photometry on TV Col during two weeks in January
(2-15) using the 0.75-m reflector with the UCT CCD in Sutherland, South
Africa.
I am calling for a campaign on TV Col during these nights. As the
candidate periodicity is relatively long, multi-longitude continuous
monitoring of the object is extremely important to reduce the aliasing
problem. So, if you can observe the object for at least ~4 h (preferably
more than one 6.4-h cycle), please let me know."
for more information, see [vsnet-campaign 579],[vsnet-campaign-ip 15]
*** General information ***
RZ Leo
Lightcurves presented by J. Pietz:
http://home.t-online.de/home/Jochen.Pietz/rzleo1.gif
http://home.t-online.de/home/Jochen.Pietz/rzleo2.gif
[vsnet-campaign-dn 354]
WY Tri
Lightcurves presented by J. Pietz:
http://home.t-online.de/home/Jochen.Pietz/wytri1.gif
http://home.t-online.de/home/Jochen.Pietz/wytri2.gif
[vsnet-campaign 641]
UV Per
Lightcurves presented by J. Pietz:
http://home.t-online.de/home/Jochen.Pietz/uvper1.gif
[vsnet-campaign 641]
VSNET collaborator's light curve presented by T. Kato:
http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/DNe/UV_Per/001229.gif
[vsnet-campaign 642]
The summary of the VSNET Weekly Campaign Summaries in 2000
"VSNET 2000" is available at:
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Summary/vsnet2000.html
(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