Rare Outburst of HT Cas
HT Cas
Rare Outburst of HT Cas
HT Cas
(vsnet-alert 3287, Eddy Muyllaert)
HT Cas is in bright outburst : mag. 12.9 on July 26.941 UT Seq. AAVSO
HT CASSIOPEIAE (UGSU+E)
July 25.931 UT, [13.3 ; 26.087, [13.6 ; 26.925, 12.5:; 27.090, 12.7 ;
27.093 UT, 12.3
Part of eclipse egress observed.
Some haze + clouds + full moon
The most recent superoutburst of HT Cas occurred in 1985 January, when the star peaked at mv= 10.8 (cf. IAUC 4027). This magnitude estimate, however, may be too bright by about one magnitude if it is based on the old AAVSO sequence. High-speed photometry during the current outburst is (of course) urgently required.
Regards,
Patrick
(vsnet-alert 3296, Zach Ioannou)
HT Cas observations at 22:25UT on July 27th show the system at about V=13.2mag (CCD + V filter). This is compared to the maximum of V=13.2 observed in the normal outburst of 1996 (Ioannou et al. Astro-ph: 9907144). The system seems to be on the decline phase of the outburst with the eclipse at 23:15UT being about 2 mags(V) deep and about 10 mins in duration.
It looks like that HT Cas underwent a really bright outburst, but not quite reaching the superoutburst region of about V=11mag.
Best regards,
Zach
(courtesy by G. Masi)
This light curve summarizes an unfiltered CCD run longer than four hours and the interruption is due to a cloud system which forced me to stop the image acquisition. The curve starts just at the end of one eclipse, while two of them are very well visible, with a dept of about 1.3 mag. The star seems to show a sort of fading all over the observing period. As regards the reference star, C1 is GSC4030:383 (located at RA 01h 10m 06.7s Dec +60d 05' 27" (J2000.0), mag 11.5), while C2 is a star in the field.
HT Cas eclipse ephemeris
Ephemeris used: HJD = 2443727.93721 + 0.073647210338 E
Time-resolved CCD photometry (10-20 sec resolution, over several hours, including eclipse phases) are extremely strongly encouraged. More information on recent two outbursts (which turned out to be normal outbursts) are available:
http://www.kusastro.kyoto-u.ac.jp/vsnet/DNe/htcas.html http://www.kusastro.kyoto-u.ac.jp/vsnet/DNe/htcas9702.html
And some practical observing schedule information at:
http://www.kusastro.kyoto-u.ac.jp/vsnet/schedule.html
Time-resolved observations of eclipsing dwarf novae (esp. with infreqent outbursts) are especially important in spatially resolving the accretion disk, and revealing the outburst mechanism. Looking forward to hearing you successful observations!
YYMMDD hh:mm:ss (UT, Geocentric) ----------------- 990726 01:17:50 990726 03:03:53 990726 04:49:56 990726 06:35:59 990726 08:22:01 990726 10:08:04 990726 11:54:07 990726 13:40:09 990726 15:26:12 990726 17:12:15 990726 18:58:17 990726 20:44:20 990726 22:30:23 990727 00:16:26 990727 02:02:28 990727 03:48:31 990727 05:34:34 990727 07:20:36 990727 09:06:39 990727 10:52:42 990727 12:38:45 990727 14:24:47 990727 16:10:50 990727 17:56:53 990727 19:42:55 990727 21:28:58 990727 23:15:01 990728 01:01:03 990728 02:47:06 990728 04:33:09 990728 06:19:12 990728 08:05:14 990728 09:51:17 990728 11:37:20 990728 13:23:22 990728 15:09:25 990728 16:55:28 990728 18:41:30 990728 20:27:33 990728 22:13:36 990728 23:59:39 990729 01:45:41 990729 03:31:44 990729 05:17:47 990729 07:03:49 990729 08:49:52 990729 10:35:55 990729 12:21:57 990729 14:08:00 990729 15:54:03 990729 17:40:06 990729 19:26:08 990729 21:12:11 990729 22:58:14 990730 00:44:16 990730 02:30:19 990730 04:16:22 990730 06:02:25 990730 07:48:27 990730 09:34:30 990730 11:20:33 990730 13:06:35 990730 14:52:38 990730 16:38:41 990730 18:24:43 990730 20:10:46 990730 21:56:49 990730 23:42:52 990731 01:28:54 990731 03:14:57 990731 05:01:00 990731 06:47:02 990731 08:33:05 990731 10:19:08 990731 12:05:10 990731 13:51:13 990731 15:37:16 990731 17:23:19 990731 19:09:21 990731 20:55:24 990731 22:41:27 990801 00:27:29 990801 02:13:32 990801 03:59:35 990801 05:45:37 990801 07:31:40 990801 09:17:43 990801 11:03:46 990801 12:49:48 990801 14:35:51 990801 16:21:54 990801 18:07:56 990801 19:53:59 990801 21:40:02 990801 23:26:04 990802 01:12:07 990802 02:58:10 990802 04:44:12 990802 06:30:15 990802 08:16:18 990802 10:02:21 990802 11:48:23 990802 13:34:26 990802 15:20:29 990802 17:06:31 990802 18:52:34 990802 20:38:37 990802 22:24:39 990803 00:10:42 990803 01:56:45 990803 03:42:48 990803 05:28:50 990803 07:14:53 990803 09:00:56 990803 10:46:58 990803 12:33:01 990803 14:19:04 990803 16:05:06 990803 17:51:09 990803 19:37:12 990803 21:23:15 990803 23:09:17
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