Date: Wed, 21 Jan 2004 13:40
From: Guillermo Stenborg
Subject: 'Full' Halo CME on 2004/01/21, frontsided
Status: O
UCMEO 93001 40121 1815/
40121 60454 81242 0001/ 360// 323// 30852
40121 60336 80536 22525 ///// 2222/
99999
PLAIN
BT
LASCO and EIT observed a 'full' halo CME on 2004/01/21. A
bright loop front was first seen in C2 at 04:54 UT at the
E limb. By 06:30 UT the loop spans ~ 175 deg from
PA 45 - 215. By 06:54 UT very faint extensions arounding
the rest of the C2 occultor are discernible. The front
first appeared in C3 images at 05:18 UT as a bright
rim above the E and SE limbs. The mean plane-of-sky speed
measured at several PA on C3 data resulted as follows:
365 km/s at PA ~0
708 km/s at PA ~75
852 km/s at PA ~110
619 km/s at PA ~140
The faintness of the front makes it impossible to make
reliable measurements on the west. The measurement at
PA ~110 is the one taken for the UCMEO code (i.e., the
fastest one).
The CME was most likely associated with a filament eruption
on the visible side of the solar disk. Between 03:36 and
05:36 UT EIT/Fe XII images show the eruption of part of a
big filament that extends from roughly the center of the solar
disk all along the SE quadrant to the SE limb. At around
04:24 UT post-event loops start to develop (at 07:25 UT
the developing of the post-event loops can be well seen
in EIT Fe XII data). GOES does not record any significant
on-disk events around the time. Neither an EIT wave nor
dimming was observed in association with the event. This
event has therefore been determined frontsided.
Images and movies will shortly be made available at
ftp://ares.nrl.navy.mil/pub/lasco/halo/20040121
Best wishes,
Guillermo Stenborg
++
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
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