Date: Wed, 10 Nov 2004 09:33
From: Guillermo Stenborg
Subject: Asymmetric 'full' Halo CME on 2004/11/10, frontsided
UCMEO 93001 41110 1430/
41110 60226 80942 0001/ 360// 123// 12900
41110 60159 80220 44909 10696 1122/
99999
PLAIN
BT
LASCO/EIT observed another asymmetric 'full' halo event on 2004/11/10.
The event was first seen in C2 at 02:26 UT above the W and NW Limb
as a very bright and wide loop front, pretty fast. By 02:50 UT, the
LE already exited the C2 FOV (the event develops mainly toward NW).
A proton storm starts developing. Faint extensions (shock?) up to NE.
The C2 occultor is completely surrounded by the faint extensions by
03:06 UT, though on SE the excess intensity is just above the occulter.
C3 images show the event starting at 02:42 UT developing toward NW. By
03:42 UT, the C3 occultor is completely covered (as in C2, the excess
intensity on SE barely above the occulter), the event having the
appearance of a very asymmetric 'full' halo event. Please note that
the 'bulk' of the mass, that is, the loop front itself only spans from
PA 215 - 010 (at 03:42 UT, measured in C3). For reference, the mean
plane-of-sky speed of the outermost layer of the 'halo' at several PA
is given below (based on C3 data; the height-time plots show practically
no acceleration):
PA 305: 2900 km/sec (*)
PA 002: 1975 km/sec
PA 221: 1477 km/sec
(*) The error is big as the outermost part becomes very diffuse.
Just for completeness, if taken as LE the brightest part of the LE
of the front at PA 305, the mean plane-of-sky speed becomes almost
2000 km/sec, pretty much alike the one at PA 002.
GOES recorded an X2.5 X-ray flare from NOAA AR 10696 (N09W49) between
01:59 - 02:20 UT with peak emission at 02:13 UT, associated to the
halo event. On the other hand, EIT 195 images show an extremely
strong brightening on NOAA AR 10696 starting at ~02:12 UT, and followed
by an intensity disturbance developing across the Sun's surface with
epicenter in the AR. Release of a huge amount of material from a big
extension on the Earth-side face of the Sun can be guessed also from
the EIT images.
In summary, the event has therefore been determined as an asymmetric
'full' halo CME, frontsided.
Movies and images of the complex event will shortly be made available
at:
ftp://ares.nrl.navy.mil/pub/lasco/halo/20041110
Best wishes,
Guillermo Stenborg
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Dr. Guillermo A. Stenborg
SOHO-LASCO Operations Scientist,
CUA, MC 682.3, 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
++