UCMEO 93001 31215 0500/ 31214 61712 82230 0001/ 360// 233// 30969 31214 61647 81712 40453 13514 1112/ 99999 PLAIN SOHO/LASCO HALO CME December 14, 2023 C2 Start Time: 17:00 - 17:12 UT C3 Start Time: 16:42 - 16:54 UT Type of CME: Asymmetric HALO CME — FRONTSIDE pa1: 000 pa2: 360 Total Width: 360 degrees Velocity Measurements: C2: 4 points 1063.4 km/sec @ PA 269.42 C3: 16 points 957.2 km/sec @ PA 269.63 Average through both(C2/C3) fields: 969.5 km/sec Acceleration: -6.33 m/sec^2 COMMENT: LASCO C2/C3 show a bright almost symmetrical halo CME. In LASCO C2, the CME emerges from the W starting at 17:00 -17:12 with bright opening lines and core. The CME propagates in all directions with the bulk portion in the west and wraps around the E by 19:00 UT.The halo CMEs source is a X2.8 flare centered on N04W53 (3514). The source is best seen on SDO AIA 171, 131, and 193 with dimming associated with the eruption towards the SE. NOAA/GOES reports a X2.8 flare from AR 13514 16:47/17:02/17:12 UT STEREO Beacon Data COR2 A, shows a asymmetric full halo. Due to gaps in data the beginning of the halo CME is not yet available. Beginning at 18:23 UT, the halo CME can be seen from all directions with bright lines though skewed partially towards the W. Preliminary time/height measurements gives a velocity of 909.2 km/sec @ PA 230.52 using 5 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/2023/231214 Best Regards, --James Tabourne BT [Images from original message are omitted here] ________________________________________________ Soho-halo-alert mailing list Soho-halo-alert@mail.nascom.nasa.gov https://mail.nascom.nasa.gov/mailman/listinfo/soho-halo-alert