Subject: SOHO/LASCO HALO CME 120209

UCMEO 93001 20212 1830/
20209 62117 80542 0591/ 058// 323// 40562
20209 61915 82135 ///// 17619 2212/
99999

PLAIN

SOHO/LASCO observed a HALO CME on February 09, 2012.  Event is first seen in
C2 at 21:17 UT as a loop event on the northeast centered at pa 55 degrees.
The event develops a defined loop with cavity and core. The front expands
with extensions to a ful asymmetric halo CME by 21:36 UT. The event continues
into the C3 field beginning 21:54 to 05:42 UT  where is leaves the field at 30 Rsun.

Time/height measurements were marked to 6 points in C2 with speeds of 512.2 Km/sec
at position angle 59 degrees. The event is marked to 11 points in C3. Speeds average
through both fields to 562.1 Km/sec at PA 59 degrees.  Acceleration 2.04 m/sec^s.


SDO/AIA 193 and 304 shows elevated filament located at [N19,E76] eruption
beginning 19:15-21:35 UT with ejecta and post loop arcade.

STEREO: Beacon data
COR2 B, 21:08-01:25 UT. Expanding bright loop with extensions, with cavity
and core over the west.
Preliminary time/height measure gives 637.6 km/sec velocity at LE. 
EUVI B, at 18:26 UT elevated prominence on NE limb, begins to lift off
at 19:26-22:36 UT. Event produces dimming of the area.
COR2 A, 21:39-02:24 UT.  Loop with core expanding over the East and NE hemisphere.
Preliminary time/height measure gives 473.6 km/sec velocity at LE.
EUVI A, n/a

NOAA reports a B7.5 Xray flare 22:01/22:07/22:17.  This flare is most likely associated
with the on disk flaring of the eruptive filament.

The observation of this event is considered 'GOOD'. This CME is determined a FRONTSIDED event.

Images and movies and time/height information for this event is available on the web at:

http://umbra.nascom.nasa.gov/lasco/observations/halo/2012/120209/

Best regards,

Kevin Schenk
Solar Heliospheric Observatory
EIT and LASCO Operations
NASA-Goddard Space Flight Center, USA

BT