SOHO/LASCO Halo CME 20230807

Halo Alert: halo-message.20230809

UCMEO 93001 30809 2300/
30809 61600 81836 1242/ 316// 133// 30938
30809 ///// ///// ///// ///// /////
99999

PLAIN

SOHO/LASCO HALO CME August 9, 2023

C2 Start Time: 16:00UT

C3 Start Time: 16:30 UT

Type of CME:
Asymmetric HALO CME — FRONTSIDE
pa1: 124     pa2: 316       Total Width: 194 degrees

Velocity Measurements:

C2:    4 points    867.4 km/sec @ PA 258.55
C3:   12 points   941.1 km/sec @ PA 258.55
Average through both(C2/C3) fields: 938.0 km/sec Acceleration: 0.20 m/sec^2

COMMENT: LASCO C2/C3 show a partial halo CME emerging from the SW then propagates in the W/SW direction. The event is associated with a backsided eruption visible from beyond the NW limb as seen best in SDO AIA 171.

STEREO Beacon Data COR2 A, shows a bright partial halo CME in the SW direction beginning at 16:23 UT. Preliminary time/height measurements gives a velocity of 1014.2 km/sec @ PA 253.53 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/2023/230809

Best Regards,

--James Tabourne

BT
[Images from original message are omitted here]

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