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[vsnet-campaign-news 121] News from VSNET
*** News from VSNET ***
WZ Sge-type dwarf nova, HV Vir is now in an extremely rare
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 January 7, 2002, as VSNET campaign circulation 1269
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
HV Vir (RA = 13h21m03s.0, Dec = +01d53'28")
On 2002 January 4, P. Schmeer discovered an extremely rare
outburst of WZ Sge-type dwarf nova HV Vir at 12mag. The last
recorded outburst occurred in 1992 (vsnet-campaign 1262,
vsnet-campaign-news 120, vsnet-campaign-hvvir 3, vsnet-campaign-dn
2026, vsnet-campaign 1263, vsnet-campaign-hvvir 6). The outburst
was also confirmed in the late January 4 at Japan (vsnet-campaign-dn
2008, vsnet-campaign 1264, vsnet-campaign-hvvir 7, 8, 12, 13).
Time-series observations have been reported by K. Torii
(vsnet-campaign-hvvir 10, 18, 24, 29, vsnet-campaign 1267), G. Masi
(vsnet-campaign-hvvir 11, 23), S. Kiyota (vsnet-campaign-hvvir 19),
R. Novak (vsnet-campaign-hvvir 28), and T. Krajci
(vsnet-campaign-hvvir 31).
Possible early superhumps were reported in [vsnet-campaign-hvvir
16]. And, double-wave, low-amplitude modulations were clearly seen
in the S. Kiyota's run, thereby early superhumps were confirmed
(vsnet-campaign-hvvir 19). T. Kato reported the period of
0.05705(3) d, which clearly indicates that the modulations are early
superhumps (vsnet-campaign-hvvir 20, 25, 26, vsnet-campaign-dn 2030,
2031). The amplitude of the variations was 0.07 mag, and then
weakened. In the late January 4, the modulation was rather
dominated by a single wave (vsnet-campaign-hvvir 21, 25, 26,
vsnet-campaign-dn 2030, 2031).
On January 5, the modulations had a low amplitude (0.06 mag)
with a complex profile. These modulations were diminishing early
superhumps. On January 6, the object suddenly started showing
genuine superhumps, with an amplitude of 0.15 mag and well-defined
superhump-type profile. It may be either that the outburst started
a few nights before the initial detection, or that the development
of genuine superhumps is more rapid than in 1992 (vsnet-campaign
1268, vsnet-campaign-hvvir 33, 37).
The outburst is still ongoing (vsnet-campaign-hvvir 17, 22, 27,
30, 35).
SS UMi (RA = 15h51m22s.4, Dec = +71d45'11".1)
A superoutburst of SS UMi was reported at 13.7mag by M. Reszelski
on January 5 (vsnet-campaign-dn 2034).
HX Peg (RA = 23h40m23s.37, Dec = +12d37'44".0)
Recently reported observations indicate that the object may
have entered a standstill (vsnet-campaign-dn 2017), but soon faded
from this short standstill on January 3 (vsnet-campaign-dn 2033).
DE CVn (RA = 13h26m54s.2, Dec = +45d32'55")
T. Kato has written in [vsnet-campaign 1259] that this binary
consists of a (presumably) white dwarf and a M-type dwarf,
resembling that of a short-period pre-CV. The orbital light curve
(cf. IBVS 4486) bears strong resemblance to the enigmatic object
CW 1045+525 (cf. A&A 380, 533), which is proposed to be a secondary-
dominated dwarf nova. Observations are encouraged.
EC 04224-2014 (RA = 04h24m41s.1, Dec = -20d07'12")
According to the EC survey, a very bright CV (B=11.6-13.0) is
discovered (MNRAS 325,89). Observations are encouraged
(vsnet-campaign 1260).
HL CMa (RA = 06h45m17s.0, Dec = -16d51'35")
Observations reported during the last week imply it started to be
in a standstill (vsnet-campaign-dn 2023). A. Henden reported ~1 mag
fainter magnitude indicating any standstill appears to be over
(vsnet-campaign-dn 2027). Visual observations also show the fading
since January 3 (vsnet-campaign-dn 2032).
BX Mon (RA = 07h25m22s.7, Dec = -03d35'50")
Observations reported by H. Maehara show the object may brighten
to 11.6mag on December 22 and confirmed on January 1
(vsnet-campaign-symbio 4).
S5-0716+71 (RA = 07h21m53s.4, Dec = +71d20'36")
The object has been reported to be relatively bright
(vsnet-campaign-blazar 241).
eta Car (RA = 10h45m03s.65, Dec = -59d41'03".7)
According to J. Garcia, eta Car may have brightened (4.8mag)
on January 3 (vsnet-campaign-sdor 1), and it was confirmed on
January 4, 5, and 6 (vsnet-campaign-sdor 2, 3, 4). Contrary to
these observations, S. Otero report that his observations show no
major brightening recently (vsnet-campaign-sdor 5).
UW Cen (RA = 12h43m16s.6, Dec = -54d31'37")
The object is slowly brightening. The current magnitude is
about 13.7mag (vsnet-campaign-rcb 9).
(continuous targets)
HT Cam (RA = 07h57m01s.2 Dec = +63d06'00")
After the rapid fading from the last bright outburst, the object
has remained relatively calm (vsnet-campaign-ip 73, vsnet-campaign-dn
2016). The long-period wave (close to the orbital period) persisted
until nearly 4 mag below the maximum. The best period determined
from the available observations is 0.064 d. The short-term
modulations (IP pulses, or QPOs?) were strong when the system was
between 14 and 15. Later on, these modulations became less
prominent, although the corresponding signal persisted
(vsnet-campaign-ip 74, vsnet-campaign-dn 2018). Mean decline rate
of HT Cam on Dec. 30 was 4.8 mag/d (vsnet-campaign-ip 75,
vsnet-campaign-dn 2019). During the decline phase, there is an
indication of two different stages of decline. The first part
resembles that of a plateau portion of a dwarf nova outburst, with a
slower decline, low amplitude of orbital (or superhump) signals, and
low amplitude of the 8 min signal. The latter part, which we have
been mostly referring to, shows much more rapid decline, large
amplitudes of orbital (or superhump) and 8-min signals
(vsnet-campaign-ip 77, vsnet-campaign-dn 2021). The data obtained
on December 31 show the fading seems to have stopped. Both
modulations seem to persist (vsnet-campaign-ip 78, vsnet-campaign-dn
2022, vsnet-campaign-ip 79, vsnet-campaign-dn 2024). T. Kato
analyzed the post-outburst light curve and reported that the 8-9 min
modulations have a rather broad power spectrum, suggesting that the
modulations have a nature of quasi-periodic oscillations (QPOs)
(vsnet-campaign-ip 81, vsnet-campaign-dn 2025). After retaining a
post-outburst plateau for three days, HT Cam started to fade again
on January 3 (vsnet-campaign-dn 2029, vsnet-campaign-ip 82). On
January 4, the dominating periodicity has changed to be 0.041 d.
The period is diffenrent from the orbital period or periods of
oscillations seen during and after the outburst (vsnet-campaign-dn
2036, vsnet-campaign-ip 83).
3C 66A (RA = 02h22m39s.6, Dec = +43d02'08")
The object is reported to be slightly active
(vsnet-campaign-blazar 240).
SN 2001el (RA = 03h44m30s.57, Dec = -44d38'23".7)
The object keeps gradually fading (vsnet-campaign-sn 306).
RR Tau (RA = 05h39m30s.53, Dec = +26d22'26".3)
As reported by G. Poyner, the object further faded
(vsnet-campaign-orion 2), and then seems to have passed the minimum
around 13.5mag on December 31 (vsnet-campaign-orion 3). The object
brightened to the 12th mag until January 5, and possibly faded
(vsnet-campaign-orion 4).
OW Gem (RA = 06h31m41s.78, Dec = +17d04'56".0)
On the ingress of an eclipse, the fading rate became faster and
faster with time and reached a minimum around January 3
(vsnet-campaign-ecl 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17),
and then the recovering from the eclipse was reported on January 4
(vsnet-campaign-ecl 18, 19, 20, 21).
V803 Cen (RA = 13h23m44s.5, Dec = -41d44'30".1)
Reported observations show that the object has rlatively been calm
at an intermediate brightness of about 14.3mag (vsnet-campaign-dn 2035).
DY Per (RA = 02h35m17s.12, Dec = +56d08'44".7)
The slow fading continues (vsnet-campaign-rcb 8).
delta Vel (RA = 08h44m42s.1, Dec = -54d42'30")
S. Otero reported observations of a secondary eclipse on 2002
January 2, and the period of 45.1501 days (vsnet-campaign-deltavel
38).
delta Sco (RA = 16h00m19s.9, Dec = -22d37'17")
The Y. Atobe's observation on January 2 may indicate it has faded
to be 2.1mag (vsnet-campaign-be 150). On the other hand,
S. Sakuma's observation on January 5 show it is still bright at
1.7mag (vsnet-campaign-be 151).
SN 2001ig (RA = 22h57m30s.69, Dec = -41d02'25".9)
This supernova brightened to the 12th mag (vsnet-campaign-sn 307,
308).
TV Col (RA = 05h29m25s.5, Dec = -32d49'05".2)
Reported observations show that the object has recently remained
calm (vsnet-campaign-ip 80).
V1039 Cen (RA = 13h55m41s.27, Dec = -64d15'57".9)
The object keeps slow fading (vsnet-campaign-nova 667).
*** Future schedule ***
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]
[vsnet-campaign-nova 666]
Blazar meeting at Tuorla: June 17-21, 2002
for more information, see http://vsnet.astro.utu.fi/blazar02
[vsnet-campaign-blazar 232]
International workshop
"XEUS - studying the evolution of the hot universe"
March 11-13, 2002 ; MPE Garching, Germany
for more information, see
http://wave.xray.mpe.mpg.de/conferences/xeus-workshop
[vsnet-campaign-xray 98]
[vsnet-campaign-xray 104]
*** General information ***
HV Vir
VSNET page for the current outburst:
http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/DNe/hvvir.html
[vsnet-campaign-hvvir 36]
QSOs near the object, see [vsnet-campaign-hvvir 5]
Recommended comparison stars, see [vsnet-campaign-hvvir 4]
[vsnet-campaign-dn 2026]
[vsnet-campaign 1263]
[vsnet-campaign-hvvir 6]
Outburst CCD image:
http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/DNe/HV_Vir/hvvir.gif
[vsnet-campaign-hvvir 9]
Field photometry presented by A. Henden:
http://ftp.nofs.navy.mil/pub/outgoing/aah/sequence/hvvir.dat
[vsnet-campaign-hvvir 32]
Charts provided by A. Price:
http://vsnet.aavso.org/charts/standard/VIR/HV_VIR/
[vsnet-campaign-hvvir 34]
HT Cam
Data presented by G. Billings:
http://vsnet.telusplanet.net/public/obs681/HTCmmc29.txt
http://vsnet.telusplanet.net/public/obs681/HTCmmc29.gif
[vsnet-campaign-data 85]
[vsnet-campaign-ip 76]
[vsnet-campaign-dn 2020]
New EC CVs:
(2000.0) catalog range
EC04030-5801 040405.73 -575327.3 UG 14.7-<18B
EC04224-2014 042441.06 -200711.5 NL 11.6-13.0B
EC05114-7955 050753.62 -795124.0 UG: 15.1B-
EC05287-5857 052928.66 -585446.5 NL 14.3-<18B
EC05565-5935 055712.65 -593525.9 NL 14.2B-
EC10565-2858 105856.40 -291440.7 UG: 14.9-16.3B
EC20335-4332 203654.57 -432231.3 UG: 14.9-15.9B
[vsnet-campaign 1261]
New list: [vsnet-campaign-hvvir]
Following the recent development of the object-oriented approach
in computer science, we have set up a new list for the present
rare outburst of HV Vir.
[vsnet-campaign-hvvir 1]
[vsnet-campaign 1265]
[vsnet-campaign 1266]
[vsnet-campaign-hvvir 14]
[vsnet-campaign-hvvir 15]
New list: [vsnet-campaign-ccd-discussion]
This list is dedicated to exchange information on CCDs and
associated techniques, data analysis softwares for conducting
VSNET campaigns. Please feel free to use the list for sharing
information.
[vsnet-campaign-ccd-discussion 1]
(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