Note on tracking Sun-Earth connection event

ICME Event: 2011/12/25

Observer: Eleni Nikou on 2019/06

1. ICME
  1.1. Catalog
     # Identified in ICME catalogs: Richardson & Can List
      RC catalog:
      Disturbance start time: 2011/12/25 02:00 UT
      Ejecta      Start time: 2011/12/25 02:00 UT
      Ejecta      End   time: 2011/12/25 17:00 UT
      dv = 0 km/s, v = 360 km/s, vmax= 370 km/s
      MC index:     1
      Dst:        -7 nT
      Suggested source CME: -
      V_transit: -
      
  1.2. Comments
      Overall ICME quality index: 2
      ICME signatures: Bmax: 4.9 nT
               ICME signatures: smooth v, smooth B, Tp<Texp after 04:00 UT
     
      Disturbance time 360 km/s  -> search window 4-5 days -> 2011/12/20

2. CME
   2.1. A. Candidate A
    A.1. LASCO:    
      #CME 2011/12/20 at 04:00:05 UT, faint partial halo CME, characterized as poor event by CDAW
           

    A.2. STEREO: 
           Also seen as a CME in COR2-A and COR2 B (first frame at COR2-A 03:54 UT)
	   Front-side CME

    A.3. AIA & GOES
	   corresponding flare: 20-Dec-2011 at 03:27 UT,
           class: B9.8,  N18W38 from AR11376

    A.4 Comment:  
	   Could be the source: The timing and orientation is in agreement with the observations

           Very small dimmings.


3. Other Comments

    CDAW gives a halo CME on 2011/12/21 at 03:12:10 UT, but it is a back-side event.

    It also gives a partial halo CME on 2011/12/21 at 09:36:05 UT, but based on the COR2 data there is no Earth directed CME.	

4. Summary
    SW index 2
    Source index 2
    Overall index 2