UCMEO 93001 31208 1700/
31207 61300 81742 0002/ 360// 233// 40728
31207 ///// ///// ///// ///// /////
99999

PLAIN   


SOHO/LASCO  HALO CME December 7, 2023 

C2 Start Time: 12:48 -  13:36 UT

C3 Start Time: 13:42 - 13:54 UT

Type of CME:
Asymmetric HALO CME — BACKSIDE
pa1:  000    pa2:  360       Total Width:  360 degrees

Velocity Measurements:

C2:   3 points     813.1 km/sec @ PA 267.50
C3:   12 points   716.7 km/sec @ PA 267.79
Average through both(C2/C3) fields:  728.8 km/sec  Acceleration: -23.73 m/sec^2

COMMENT:  LASCO C2/C3  show an asymmetric halo emerging in all directions with a bright leading edge to the W. In LASCO C2 imagery a bright core can be seen emerging from the W as as the halo begins at approximately 13:36 UT. Due to no source being seen on the frontside, the source is likely a backsided eruption with evidence of field line movement beyond the NW limb seen in SDO AIA 171 imagery beginning at 13:00 UT.

STEREO Beacon Data COR2 A, shows a faint asymetric halo emerging from all directions,  between 13:23 - 13:53UT. The halo propagates outward in all directions skewed towards the west. Preliminary time/height measurements gives a velocity of 749.2 km/sec @ PA 227.50 using 6 points of measurement.

Preliminary UCMEO velocity and position measurements are delivered first.
Images, movies, and time/height information for this event will be available at:

https://umbra.nascom.nasa.gov/lasco/observations/halo/2023/231207



Best Regards,

--James Tabourne

BT
[Images from original message are omitted here]

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