complied data from VSNET reports
(vsnet-alert 273, G. Poyner)
Dear Colleagues,
Bill Worraker (Didcot, UK) has reported an outburst of HT Cas, which is monitored as part of the TA/BAA Recurrent Objects Programme. I have just confirmed the outburst. Details....
Nov 17.9049 UT mv=13.4 Worraker, 26cm Seq. TA
17.9132 mv=13.4 Poyner, 40cm Seq. TA
There is no need to emphasise the importance of this outburst!
Regards,
Gary Poyner
***************************************************************** Details of the Recurrent Objects Programme can now be found on 'THE ASTRONOMER' WWW pages at http://www.demon.co.uk/astronomer *****************************************************************
Dear Colleagues,
We Ouda-team observed HT Cas on Nov 15 with a CCD with V filter attached to a 60-cm reflector. HT Cas was found to be already somewhat brighter than usual quiescent level at that time with an averaged level of V=16.14 outside eclipses. An eclipse was observed approximately centered at HJD24450037.147, with a duration of 12 min which is apperently longer than mentioned (~6 min) by Welsh (vsnet message #317). No evidence of orbital hump was observed.
For follow-up observers, a PostScript finding chart with V-magnitude is available at :
ftp://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/charts/HT_Cas.ps.
The forecast time of eclipses of HT Cas are listed below
(times are geocentric).
YYMMDD hh:mm:ss (UT)
951118 05:16:20
951118 07:02:23
951118 08:48:27
951118 10:34:30
951118 12:20:33
951118 14:06:36
951118 15:52:39
951118 17:38:43
951118 19:24:46
951118 21:10:49
951118 22:56:52
HJD (mid-eclipse) = 2443727.93721 + 0.0736472039E
And the table of comparison stars are listed below.
AAVSO Misselt(1995) VSNET
(Alert 217) V B-V approx. V
----------------------------------------------
95
101
104
106
109 11.88 +0.59 11.84
(113)
115
124
127
134 13.62 +0.85
136
anon 13.92 +0.85 13.90 just south of HT Cas
143 14.33 +1.59 14.23
anon 14.61 +1.02 14.62 west to AAVSO (109)
151 14.70
155 15.19 +1.86 15.19
156 15.02
anon 15.58 +1.79 15.57 faint star just SE to HT Cas
159 15.82
163 16.18
166 15.91
Needless to say, close monitoring is highly encourged.
Best Regards,
Hajime Baba and Ouda-team
Eclipse observations at Ouda
Dear Colleagues,
A total of high quality 1081 V-band CCD frames of HT Cas were obtained
by a 60-cm reflector at Ouda Station (Kyoto University) with a typical time
resolution of 23s (20s exposure + 3s dead time). A prelimary analysis
gives following mid-eclipse times (heliocentric correction has not been
applied intentionally). Magnitudes were determined using V=11.88 star
by Misselt (1995).
JD (Geo) eclipse center outside eclipse depth
2450039.86757 14.45 V 13.16 V 1.29 V
40.01482 14.45 13.17 1.28
40.08851 14.50 13.22 1.28
40.16218 14.57 13.26 1.31
40.23583 14.72 13.29 1.43
Eclipses last ~12 min. The above data seem to indicate HT Cas has already
started a rather rapid decline at a rate of ~0.5 mag/day. However, broad hump
features (amplitude ~0.05 mag) around 2450040.108 and 2450040.190 may be
indicative of the appearance of superhumps. Further observations are
strongly encouraged.
Regards,
Ouda team (Daisaku Nogami and Hajime Baba
observing)
Start of a rapid decline
Dear Colleagues,
We Ouda Team observed HT Cas on Nov 19.47. The object seems to be
declining. Based on our CCD image on CRT, we estimate that the
magnitude out of eclipse is V~13.7 mag, which is about 0.6 mag fainter
than that of Nov 18. This indicates that this outbutst seems to be a
normal one ?
Further monitoring is highly encourged !
Best Regards,
Hajime Baba and Daisaku Nogami
Ouda Team ( at observatory )
Eclipse observation by
Makoto Iida
This image contains consecutive eight panels, from the upper left
to the lower right as time proceeds. HT Cas is the northern component of
an aggregate of three stars at the center of each panel. The fourth
panel represents the center of an eclipse. The images were taken by
a 16-cm reflector with an ST-6 CCD camera. (Courtesy of Makoto Iida)
Outburst image by the Ouda team
CCD photometry by Nick James
Dear all,
Attached to this e-mail is a postscript graph showing two consecutive eclipses
of HT Cas. Photometry was unfiltered using a Sony CCD and 30cm Newtonian
and the brightness of HT Cas was measured relative to the nearby
GSC 4030.00719. Eclipse duration was 550 sec in each case and the times of
minima were:
1995 November 19, 18:24:20 UTC (JD 2450041.26690)
1995 November 19, 20:10:30 UTC (JD 2450041.34063)
These agree very well with predictions based on Kato's vsnet-alert 277 message.
The sample period in the following plot is approximately 25s (20s exposure
+ 5s read-out). My location is Chelmsford, UK.
More information, including a CCD image of the field is available on the
pages of The Astronomer at
http://www.demon.co.uk/astronomer/htcas.html
Regards Nick James.
get a full message containing a PS file
Post-outburst behavior
Dear HT Cas observers,
HT Cas seems to have stopped fading. The post-outburst object is now
staying about 1 mag brighter than its "high-state" quiescence. Nightly
averaged preliminary magnitudes outside eclipses are below:
mid-UT mag S.D. N band
-----------------------------------
951118.618 13.27 0.075 904 V
951119.505 13.98 0.086 71 V
951120.534 15.55 0.130 91 V
951121.554 15.89 0.141 477 V
951122.494 15.93 0.210 303 V
(S.D.: for a single point)
The light curves on Nov. 21 and 22 show broad undulations with a time-
scale of few hours, together with short-term flickering and QPOs. Although
the averaged system brightness has changed little these two nights, the
shapes of eclipses have changed considerably; the system is now exhibiting
rather sharp ingresses and egresses which are usually observed in quiescence.
Regards,
Ouda team (Taichi Kato, observing)
Related objects
vsnet-adm@kusastro.kyoto-u.ac.jp
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