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[vsnet-campaign-news 43] News from VSNET 43
*** News from VSNET ***
W. Liller discovered a bright nova in Sagittarius on February 24.
The current magnitude of this nova is ~9mag.
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 Feb. 27, 2001, as VSNET campaign circulation 797.
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
Nova Sgr 2001 (RA = 17h54m40s.43, Dec = -26d14'15".7)
W. Liller discovered an apparent nova on February 24 (mag 7.7)
(vsnet-campaign-nova 223). A. Jones confirmed the object at 8.9mag
on February 25 (vsnet-campaign-nova 226). H. Nishimura has
independently detected the object (vsnet-campaign-nova 233,
239, 240). K. Kadota reported his result of astrometry and
noticed that there is a USNO_A2.0 star (rmag = 15.8, bmag = 17.4)
near the nova (vsnet-campaign-nova 227, 232). H. Yamaoka mentioned
that a faint star with rmag about 18 is also seen in DSS2R image
(vsnet-campaign-nova 228). Early photometry reported by some
observers shows the current magnitude is around 9.1mag
(vsnet-campaign-nova 229, 230, 231, 243, 235, 241).
K. Torii performed astrometry which yields results consistent with
others (vsnet-campaign-nova 234). K. Takamizawa's negative
observation revealed the nova eruption occurred after February 19
(vsnet-campaign-nova 236). T. Kato mentioned that it may be a
recurrent nova in the case of the 16-17th mag star is the quiescent
object. In such a case, the evolution of the nova may be extremely
rapid (vsnet-campaign-nova 238).
SN 2001V (RA = 11h57m24s.93, Dec = +25d12'09".0)
IAUC 7585 reports that the CfA group has discovered the new
type Ia SN. The position is 52" east and 28" north of the
edge-on spiral galaxy NGC 3987. This galaxy has a remarkable
dust lane, and SN 2001V lies just south of the disk plane.
NGC 3987 is a member of the group of galaxies, which is sometimes
called as "NGC 4005 group". Although it is in the direction of the
Coma supercluster, this group lies in front of the Coma; the mean
recession velocity is about 4600 km/s. Thus, the expected maximum
for the typical SN Ia is about 15.5 mag (vsnet-campaign-sn 154, 155).
TU Men (RA = 04h41m38s.10, Dec = -76d36'09".7)
A possible outburst (14.1: mag) of the SU UMa-type dwarf nova,
TU Men was reported by P. Nelson on February 20. R. Stubbings
reported that the object further rose to 12.6mag (vsnet-campaign-dn 513).
The object then further brightened to 11.8mag on February 21 and 22
(vsnet-campaign-dn).
DW Cnc (RA = 07h58m56s.80, Dec = +16d16'48".2)
M. Reszelski reported the object was fainter than and as bright
as 14.5 mag on 2000 September 25 and 2001 February 18, respectively.
This indicates an outburst occurred during the last week, but there
is no previous firm faint state observation (vsnet-campaign-dn 514, 527).
T. Vanmunster mentioned the object is always around 14.5+/- 0.5 mag,
and this activity may not be a genuine outburst (vsnet-campaign-dn 531).
DI UMa (RA = 09h12m22s.16, Dec = +50d49'39".1)
M. Reszelski reported an outburst (15.7: mag) of DI UMa on
February 18. The outburst may be a superoutburst (vsnet-campaign-dn 524).
CP Dra (RA = 10h15m39s.88, Dec = +73d26'05".4)
As reported in [vsnet-outburst 1691] by C. Jones on February 23,
the poorly known dwarf nova CP Dra is undergoing a rare, bright
(14.3mag) outburst. The last outburst was observed on 2000 May 15
by T. Vanmunster (vsnet-alert 4851). That outburst was mag 15.3
and relatively rapidly faded. The brightness of the present
outburst surpasses that of the GCVS maximum (15.1) and other
available records (vsnet-campaign 788). T. Vanmunster reported the
detection of superhumps with an amplitude of 0.3mag and a period of
0.0687 +/- 0.0007 day (vsnet-campaign 793). He also performed
astrometry and reported the position (vsnet-campaign-dn 532).
H. Yamaoka also performed astrometry and reported the above
position (vsnet-campaign-dn 533, 534). The Kyoto team confirmed
the outburst on February 24 (vsnet-campaign 789, vsnet-campaign-dn 529),
and reported the growth of superhumps with an amplitude of 0.2mag
with a period of 0.078 day, which is significantly longer than that
reported by T. Vanmunster (vsnet-campaign 792, 794).
The superoutburst is now ongoing (vsnet-campaign-dn 538, 539, 540).
OI 090.4 (RA = 07h57m06s.6, Dec = 09d56'35")
The blazar OI090.4 has brightened to V=15.6mag as reported by
S. O'Connor on February 24 (vsnet-campaign-blazar 156).
CR Boo (RA = 13h48m55s.42, Dec = +07d57'30".3)
The object experienced a bright (13.7mag) outburst on February 24
as reported by M. Reszelski (vsnet-campaign-dn 537).
KR Aur (RA = 06h15m45s.05, Dec = +28d34'16".0)
As reported by some observers, the nova-like variable KR Aur
is brightening now (vsnet-campaign-nl 5).
(continuous targets)
BZ Cam (RA = 06h29m34s.49, Dec = +71d04'39".5)
After rapid recovering, the object again showed fading
(vsnet-campaign 787, vsnet-campaign-nl 4). A possible brightening
was reported on February 25 (vsnet-campaign-nl 6, vsnet-campaign 796).
SAX J1711.6-3808 (RA = 17h11m36s, Dec = -38d08'.5)
H. Yamaoka performed astrometry using CCD images taken by the
Kyoto team. According to his result, there are two stars somewhat
brighter than DSS R image. One is an USNO_A2.0 star at R.A. =
17:11:36.40, Decl. = -38:08:16.3 (2000.0), whose rmag = 15.4
bmag = 18.9. It appears on Kyoto image to be 14.8:C.
And, another one is located at R. A. = 17h11m39s.15, Decl. =
-38o07'52".7 (2000.0), which is not cataloged in USNO_A2.0, but
can be seen on DSS2 R and Bj image. The rough magnitude estimates
on DSS are r = 17.6, b = 19.5. It appears on Kyoto image to be 16.0:C.
These are possibly red stars (vsnet-campaign-xray 64). The Kyoto
team have taken additional images on February 21 (vsnet-campaign-xray 65).
TT Boo (RA = 14h57m46s.46, Dec = +40d43'55".5)
The superoutburst continues (vsnet-campaign-dn 515, 525, 530, 535, 541).
TV Crv (RA = 12h20m23s.56, Dec = -18d27'02".7)
The superoutburst continues (vsnet-campaign-dn 509, 512, 526, 536).
The striking feature in the Feb. 19 light curve obtained by the
Kyoto team is the presence of "super-QPOs", giant quasi-periodic
oscillations only seen at the early (or fading) epochs of some
SU UMa-type systems. The super-QPOs in TV Crv had an amplitude
of ~0.1 mag, and a typical period of 10 min. The Kyoto observation
on Feb. 20 (Uemura et al.) has shown fully developed superhumps.
The development of superhumps took 2 or 3 days after the ignition
of the outburst. The best superhump period is 0.0649 d, which
confirms the previous estimate (0.0650 d, Howell et al.).
This finding confirms that TV Crv is one of short orbital period
systems (vsnet-campaign 785, 786). During February 18 - 21,
the object was gradually faded with a rate of 0.03-0.05mag/day
(vsnet-campaign-dn 518). In the light curve taken on February 20-24
at Kyoto, we can see prominent superhumps with slightly smaller
amplitude. Period analysis using combined data yields 0.06492 d
(vsnet-campaign-dn 522, vsnet-campaign 795).
U Gem (RA = 07h55m05s.55, Dec = +22d00'09".2)
The object is still slightly active (vsnet-campaign-dn 511, 517, 528).
The recent activity is unusual for this object (vsnet-campaign-dn 519).
V445 Pup (RA = 07h37m56s.88, Dec = -25d56'59".1)
Some observers reported the object was slightly bright (~9.8mag)
on February 19 and 20 (vsnet-campaign-nova 218), and then,
relatively calm on February 21 - 26 (vsnet-campaign-nova 222, 224, 242).
The VSNET collaboration team received data sets obtained by A. Retter,
G. Handler, and M. Martigoni. Combined light curve during February
10 - 19 shows short-term modulations with a time-scale from ten
minutes to an hour, and longer scale (a few days) variations.
Amplitudes of the short-term modulations are variable, but typically
0.03mag in V-band (vsnet-campaign-nova 219). The light curve
on February 22 taken at Kyoto also shows small-amplitude variations
with time-scales of 10-30 min (vsnet-campaign-nova 221).
The Kyoto data of V445 Pup on Feb. 24 has shown that the object may
have entered an active phase (vsnet-campaign-nova 225).
Delta Sco (RA = 16h00m19s.9, Dec = -22d37'17")
The object is still active (vsnet-campaign-be 90).
V803 Cen (RA = 13h23m44.5s, Dec = -41d44'30".1)
The object faded from the outburst on February 20
(vsnet-campaign-dn 510).
GK Per (RA = 03h31m12s.50, Dec = +43d54'17".8)
The slightly active state continues (vsnet-campaign-ip 43).
MKN 421 (RA = 11h04m27s, Dec = +38d12'32")
The active state continues (vsnet-campaign-blazar 153, 154, 155).
L. Takalo noticed that Mrk 421 has brightened quite a lot at
TeV- energies, showing also very rapid variability
(vsnet-campaign-blazar 157).
CI Aql (RA = 18h52m03.6s, Dec = -01d28m38.9s)
This recurrent nova is reported to be still bright in this season.
S. Kiyota reported V=14.17, Ic=13.64, and Rc=13.96 On February 16.
Such activity is quite unusual for this type variable
(vsnet-campaign-nova 220).
*** Future schedule ***
RZ LMi campaign conducted by J. Patterson on April 2001
For more information, see [vsnet-campaign 718, vsnet-campaign-dn 429].
MAXI workshop on AGN Variability
March 10-11, 2001, Nikko, Japan, Organized by RIKEN & NASDA
For more information, see [vsnet-campaign-blazar 144]
*** General information ***
U Gem
Eclipse ephemeris, see [vsnet-campaign-dn 521]
CP Dra
The outburst image taken at Kyoto:
http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/DNe/CP_Dra/cpdra.gif
[vsnet-campaign 791]
Nova Sgr 2001 VSNET page:
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Novae/nsgr01.html
[vsnet-campaign-nova 237]
(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