Date: Fri, 3 Sep 2004 14:02
From: Guillermo Stenborg
Subject: Another 'full' Halo CME on 2004/09/03, backsided
UCMEO 93001 40903 1800/
40903 61030 91742 0002/ 360// 123// 20692
///// ///// ///// ///// ///// /////
99999
PLAIN
BT
LASCO/EIT observed a second 'full' halo CME on 2004/09/03.
The event was first observed in C2 at 10:30 UT as a very
faint and diffuse circular front in the northern hemisphere,
brighter above the ENE Limb. By 10:54 UT the C2 occultor is
completely surrounded. By that time, a brighter front begins
to be visible above the E Limb up to the S Pole. Inspection
of the C2 running difference movie shows an almost perfect
circular front inside the diffuse circular front described
at the beginning. The C3 occultor is completely surrounded
by this second feature at 11:42 UT. For reference, the mean
plane-of-sky speed for the LE of the various features is
given below (based on C3 data):
- LE of the diffuse circular front at PA 120: 692 km/sec
(practically no acceleration)
- LE of the second circular front at PA 115: 517 km/sec
(practically no acceleration)
GOES did not record any significant X-ray activity by the
time. Likewise, EIT Fe XII images do not show any signature
that could be related to the Halo event.
The event has therefore been determined as a 'full' halo
CME, backsided.
Images and movies of the event will shortly be made available
at:
ftp://ares.nrl.navy.mil/pub/lasco/halo/20040903b
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
++