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[vsnet-campaign-news 26] News from VSNET 26
*** News from VSNET ***
Some poorly studied objects are now in outburst. RX J2315.5-3049,
turned out to be an SU UMa-type dwarf nova through observations
of the outburst.
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 Oct. 31, 2000, as VSNET campaign circulation 545.
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
KW And (RA = 02h35m17s.991, Dec = +41d14'02".47)
T. Kinnunen found the large-amplitude dwarf nova KW And is in outburst
at the magnitude of 15.0 on October 22. The last outburst was observed in
2000 March (vsnet-campaign 537). From 2-hour time-series observation on
October 26, Ouda team reported a possible short-term modulation with its
amplitude of 0.2mag (vsnet-campaign 540). H. Yamaoka performed astrometry
using Ouda image, and reported the accurate position as above. It seems
secure that the USNO_A2.0 star at (end figures) 18s.00, 02".1 is identical
to KW And, whose USNO_A2.0 rmag = 17.8 and bmag = 18.6. It seems that
Kurochkin, 1977 is the only one reference of the type identification (UG)
and the GCVS minimum magnitude(22:p) (vsnet-campaign-dn 224).
SN 2000dw (RA = 22h13m49s.06, Dec = +39d14'15".1)
H. Yamaoka wrote in [vsnet-campaign-sn 104] that Beijing group discovered
a new supernova, SN 2000dw in Scd galaxy UGC 11955 at mag 17.5:C.
The position is just a few arcseconds NE of the nucleus of the host.
The recession velocity of the host galaxy suggest that the normal SN Ia
without extinction would become mag 16 at its maximum.
DM Dra (RA = 15h34m01s.33, Dec = +59d47'02".0)
P. Schmeer reported a rare outburst of DM Dra, a large amplitude dwarf
nova. The magnitude reached 14.1 on October 18 (vsnet-campaign-dn 213).
T. Kato commented that the object had been monitored visually for several
years, but there was no confirmed outburst reported to VSNET, except two
suspected sightings by T. Kinnunen (1998 Sep. 25, 16.0: and 2000 Sep. 30,
15.9:). The current brightness and the duration of outburst very strongly
suggest a superoutburst (vsnet-campaign 538).
RX J2315.5-3049 (RA = 23h15m31s.934, Dec = -30d48'45".53)
As reported by R. Stubbings in [vsnet-outburst 810], RX J2315.5-3049 is
now undergoing an outburst. Ouda team confirmed the outburst at the
magnitude of R=14.2 on October 26 (vsnet-campaign 539). On October 27,
Ouda team found the object is brighter with the magnitude of R~13.6
(vsnet-campaign 542). From their preliminary reduction, they detect clear
superhumps in ~3 hours light curve, which establishes this object is a new
member of SU UMa-type dwarf nova. The period of the superhumps is about
0.078 d and the amplitude is about 0.3mag (vsnet-campaign 544).
V1113 Cyg (RA = 19h22m38s.62, Dec = +52d43'51".1)
On October 21, it was reported that the dwarf nova, V1113 Cyg was in
outburst at the magnitude of 13.8-14.0. The object was then faded
to <14.5 on October 23. T. Kato commented the October 21 outburst may have
been a precursor to superoutburst (vsnet-campaign-dn 211).
GRB 001025A (RA = 08h36m36s.5, Dec = -13d04'30")
The RXTE All-Sky Monitor has detected a gamma-ray burst, beginning at
about 03:10:05 UTC on 25 Oct 2000 (vsnet-grb 24). B. Skiff presents
the sequence of the field in [vsnet-grb 26]. Ouda team took CCD images
with 60-cm telescope on October 26.79 and no new object has not detected
within the error box under the limiting magnitude of R=18 (vsnet-grb 27, 30).
GRB 001025B (RA = 18h21m40s.78, Dec = -05d8'34".45)
Ulysses, NEAR, and KONUS-WIND observed this GRB at 71369 seconds.
Ouda team taken CCD images with 60-cm telescope on October 27 9:00 (UT)
(vsnet-grb 29).
(continuous targets)
V544 Her (RA = 16h38m03s.20, Dec = +08d37'04".2)
C. Kunjaya reported the results of photometry of V544 Her on October 19
(vsnet-campaign-dn 217).
IP Peg (RA = 23h23m09s.07, Dec = +18d25'10".4)
J. Pietz performed a time-series observation on October 22 and reported
the object brightened with a rate of ~2mag/d and eclipses with an amplitude
of 2.5mag (vsnet-campaign-dn 209). The outburst is now ongoing.
The current magnitude is about 12.4-12.9 (vsnet-campaign-dn 223).
BL Lac (RA = 22h02m42.86s, Dec = +42d16'37.6")
The object was slightly faded in the last week. The reported magnitude
was 13.9-14.5 (vsnet-campaign-blazar 85, 87).
SN 2000ds (RA = 09h11m36s.24, Dec = +60d01'42".2)
A. V. Filippenko reports on IAUC 7511 that SN 2000ds would be of
type Ib SN. The spectrum suggests that it is an old supernova
(vsnet-campaign-sn 104).
PKS 2005-489 (RA = 20h05m47.4s, -48d58'45".0)
The bright state continues. The current magnitude is about 12.3mag
(vsnet-campaign-blazar 86).
SY Vol (RA = 08h53m28s.9, Dec = -71d12'29".9)
The another outburst was detected by R. Stubbings on October 27
at the magnitude of 14.5 (vsnet-campaign-dn 218).
*** General information ***
IY UMa
A. Oksanen calculated a new eclipse ephemeris using eclipses observed
during January, April, and September outbursts:
T = 2451818.30578( +/- 0.00017) + 0.07391213( +/- 0.00000020) * E
[vsnet-campaign 541]
RX J2315.5-3049
CCD image taken at Ouda observatory on October 27:
http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/DNe/J2315/rxj2315.gif
[vsnet-campaign 543]
(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