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[vsnet-campaign-news 25] News from VSNET 25
*** News from VSNET ***
S. Otero and C. Lloyd found a candidate of the orbital period of Delta Vel
to be ~45 days, and the next eclipses will occur on Nov. 1 and 21 if it is
the case.
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. 24, 2000, as VSNET campaign circulation 536.
[Note a large part of detailed information is posted to vsnet-campaign
sub-lists].
VSNET Weekly Campaign Summary
*** Last week news ***
(new targets)
V544 Her (RA = 16h38m03s.20, Dec = +08d37'04".2)
As reported by P. Schmeer, an outburst of V544 Her was detected,
and then, confirmed by T. Vanmunster on October 17, and M. Uemura and
T. Kato on October 18 [vsnet-alert 5327, 5328, vsnet-campaign-dn 200, 202,
and 205]. At the peak on October 17, the magnitude was about 16
(vsnet-campaign-dn 205).
CH Her (RA = 18h34m46s.21, Dec = +24d47'57".0)
M. Uemura and T. Kato confirmed an outburst of CH Her which was reported
by G. Hanson on October 18. The magnitude was about R=14.8
(vsnet-campaign-dn 201).
KZ Gem (RA = 06h52m59s.26, Dec = +16d40'16".4)
Following a notification by P. Schmeer, M. Uemura and T. Kato confirmed
an outburst of KZ Gem on October 18. The R-magnitude was about 14.2
(vsnet-campaign-dn 204). During the run by them, no variation with an
amplitude over 0.1mag was not seen (vsnet-campaign-dn 204).
HD 5980 (RA = 00h59m26s.5, Dec = -72d09'54")
Rapid fading of this object was detected from observations by A. Pearce
(vsnet-sdor 9). The magnitude reached 11.4 on October 17. About this
fading, T. Kato forwarded a message from Dr. Koenigsberger in
[vsnet-campaign 532]. According to it, the fading phase correspond to the
orbital phases between 0.2 and 0.4 (P=19.266) which coincide with the
eclipse of Star A (the LBV/eruptor) by Star B (presumably the original WR
star), although a drop by 0.7mag does seem a LARGE drop for visual
magnitudes.
RX J0909.8+1849 (RA = 09h09m50s.5, Dec = +18d49'47")
P. Schmeer reported an outburst of this eclipsing dwarf nova
on October 17 at the magnitude of 13.5 (vsnet-campaign-dn 206).
AB Dra (RA = 19h49m06s.37, Dec = +77d44'43".1)
T. Kato commented from the last week observations that the short-period
Z Cam star AB Dra may be entering a standstill on October 20
(vsnet-campaign 533). He also reported an outburst on October 20 and it
is not a true standstill, but a bright minimum before the outburst
(vsnet-campaign-dn 207).
IP Peg (RA = 23h23m09s.07, Dec = +18d25'10".4)
An outburst of an eclipsing dwarf nova, IP Peg was reported on
October 22 (vsnet-outburst 782).
(continuous targets)
Delta Vel (RA = 08h44m42s.1, Dec = -54d42'30")
S. Otero reported some observations on Delta Vel; according to
D. Overbeek, no eclipse was seen between JD 2451832.5486 and 2451832.6250.
R. Salvo seems to have noticed a possible dimming between JD 2451832.7251
and 2451832.8333. Paul D Fieseler informed to S. Otero that another fading
was recorded by Galileo's star scanner in 1989 (JD 2447850.3 - 2447851.0).
This fading doesn't fit with the ephemeris unless the period is decreasing
at a fast rate. However this trend seems not to be present in the last
eclipses. With the Galileo's data, S. Otero and C. Lloyd suggested that
the dimmer point observed by Hipparcos is not a real eclipse but an
observation with large dispersion. They furthermore found a period of
45.16 days and both primary and secondary eclipses are obserbed
(vsnet-deltavel 3, 4, 5).
The ecipse ephemeris predicts the next primary eclipse will occur
on November 1 22:22 (UT) and the next secondary eclipse will occur
on November 21 19:18 (UT) (vsnet-campaign-deltavel 4). The observations
are strongly encouraged.
CI Aql (RA = 18h52m03.6s, Dec = -01d28m38.9s)
The last week observation reported to VSNET shows steeper fading
of CI Aql. The object currently seems to be about 14mag
(vsnet-campaign-nova 85).
BL Lac (RA = 22h02m42.86s, Dec = +42d16'37.6")
BL Lac continues its large amplitude and rapid activity. The observations
of 13.7 - 14.5 during the last night were reported to VSNET
(vsnet-campaign-blazer 82, 83).
3C 66A (RA = 02h22m39s.6, Dec = +43d02'08")
A brightening of this blazer was reported in the end of September, and
then, the object was dimmer until another brightening was reported in
last week. On October 19, C. P. Jones reported the magniutde of 14.5
(vsnet-campaign-blazer 84).
SN 2000cx (RA = 01h24m46s.15, Dec = +09o30'30".9)
The fading continues. The current magnitude is about 17.2 (on October 19
observation by C. Leyrat; vsnet-campaign-sn 103).
MV Lyr (RA = 19h07m15s.93, Dec = +44d01'10".7)
The object is now at very faint state. S. O'Connor reported V-magnitude
is fainter than 17.0 on October 20 (vsnet-campaign-nl 3).
*** General information ***
Delta Vel
eclipse ephemeris, see [vsnet-campaign-deltavel 8]
IP Peg
eclipse ephemeris, see [vsnet-campaign-dn 208]
New VSNET mailing lists: vsnet-constel-
We have set new VNSET mailing lists, [vsnet-constel].
These presents recent observations reported to VSNET of variable stars
grouped with each constellation for subscribers. If you want to know
current state of objects in, for example, Gemini (gem), you should subscribe
[vnset-constel-gem] as below:
mail to "vsnet-adm@kusastro.kyoto-u.ac.jp"
write in the text;
SUBSCRIBE vsnet-constel-gem your_e-mail_address
(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