Subject: SOHO/LASCO HALO CME 110113 BACKSIDED

UCMEO 93001 10113 2115/
10113 60936 81854 3242/ 164// 233// 40532
10113 60835 80906 ///// 11141 1112/
99999

PLAIN

SOHO/LASCO observed an asymmetric PARTIAL HALO CME on January 13, 2011.  Event is first seen in 
C2 at 09:36 UT as a bright defined loop over the northeast quadrant.  The event expands
with material spanning PA 324 - 164 degrees for a total of 200 degrees wide.
The event is seen in first frame of C3 at 10:06 UT and tracked out to 18:54 UT at 
25.0 Rsun where the event dissipates.
 
Time/height measurements were marked to 6 points in C2 with speeds of 598.1 km/sec, the event
decelerates in C3, marked at 16 points and calculated to velocities averaging thru both fields
to 532.0 Km/sec at position angle 68 degrees.    

STEREO EUVI 195A Behind beacon data shows a flare of AR 11138 in it's northeast quadrant 
beginning 08:36 - 09:06 UT with a sizeable EUVI wave and post arcade.  The wave can account
for the material extensions seen in C2 to define a partial HALO.
There were no Earthward facing events or activity.
   
The observation of this event in LASCO is considered 'good'. This CME is determined a BACKSIDE 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/2011/110113/

Best regards,

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

BT