Date: Fri, 15 Dec 2006 12:57
From: Guillermo Stenborg
Subject: Potential asymmetric Full Halo Event on 2006/12/14, frontsided
Status: O
UCMEO 93001 61215 1700/
61214 62230 92342 0001/ 360// 133// 21220
61214 62107 82226 34606 10930 1112/
99999
PLAIN
LASCO/EIT observed what would appear to be an asymmetric Full Halo
Event on 2006/12/14-15 (incomplete LASCO imagery by the time of writing).
The event was first seen in the LASCO C2 FOV on 12/14 at 22:30 UT as a
very bright loop front on the WSW Limb with diffuse extensions to N. By
23:30 UT, the bulk of the CME (which heads toward SW as projected onto
the plane of the sky) reached the outer edge of the C2 FOV, while the
diffuse extensions (on W) are already well past the outer edge. An
increase of cosmic rays can be seen by this time. The event is first seen
in C3 on 12/14 at 23:42 UT, all above the SW Limb with faint and diffuse
extensions to the sides of the bulk of the CME. The mean plane-of-sky
speed for the LE of the bulk of the CME at PA ~ 237 was about 970 km/sec.
On the other hand, if measured on the LE of the extensions surrounding the
bulk of the CME at PA ~ 263, the plane-of-sky speed amount ~ 1220 km/sec.
Note that the measurements were based on only a couple of C2 frames and
just one C3 frame due to the no availability of the "reformated" LASCO
data at the time of writing at our offices (we had yesterday a disk
failure on one of the LASCO operations machines and are right now in the
process of recovering).
GOES recorded a X1.5 X-ray flare on NOAA AR 10930 (S06W46) on 12/14
between 21:07 - 22:26 UT with peak emission at 22:15 UT. EIT 195 images
show a brightness increase on AR 10930 at 22:00 UT, the brightening
becoming strongest at 22:12 UT. A rather circular wave (and dimming)
with epicenter on the AR mentioned can be seen afterwards, developing
almost all the way to the far Limb (East). By 23:12 UT, a slight increase
on cosmic rays can be detected on EIT 195 images.
In summary, based on the few LASCO images available the event has
therefore been determined as a potentially asymmetric full halo event,
frontsided associated to the X-class event that occurred late on 12/14
on AR 10930.
Movies and images of the event will shortly be made available at:
ftp://ares.nrl.navy.mil/pub/lasco/halo/20061214
Please again note that the movies will be rather incomplete due to the
disk failure mentioned above. As son as the machine involved is recovered,
the movies will be upgraded (there will be no loss of imagery).
Best wishes,
Guillermo Stenborg
++
Dr. Guillermo A. Stenborg
SOHO-LASCO Operations Scientist,
CUA, MC 612.5, Bldg 26, Rm 001, F: +1-301-286-0264
NASA Goddard Space Flight Center,
Greenbelt, MD 20771. P: +1-301-286-2941
e-mail: stenborg@kreutz.nascom.nasa.gov
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