Note on tracking Sun-Earth connection event

ICME Event: 2011/12/29

Observer: Eleni Nikou on 2019/06

1. ICME
  1.1. Catalog
     # Identified in ICME catalogs: Richardson & Can List
      RC catalog:
      Disturbance start time: 2011/12/29 22:00 UT
      Ejecta      Start time: 2011/12/29 22:00 UT
      Ejecta      End   time: 2011/12/30 09:00 UT
      dv = 0 km/s, v = 400 km/s, vmax= 420 km/s
      MC index:     1
      Dst:        -16 nT
      Suggested source CME: 12/26/2011
      V_transit: -
      
  1.2. Comments
      Overall ICME quality index: 2
      ICME signatures: Bmax: 8.5 nT
               ICME signatures: smooth v, smooth B, Tp<Texp until 09:00 UT
      
      Disturbance time 400 km/s  -> search window 4-5 days -> 2011/11/25

2. CME
   2.1. A. Candidate A
    A.1. LASCO:    
      #CME 2011/12/25 	01:25:53 UT, 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 01:24 UT)
	   Front-side CME

    A.3. AIA & GOES
	   There is no corresponding flare given by GOES or Solar Monitor.
           
           After using multiwavelength observations it turns out that there was a filament eruption around 00:00 UT on 2011/12/25, located at the nothern western hemisphere. The location of the eruption is in agreement with the orientation of the partial halo CME at C2 and the CME at COR2.

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


   2.1, B, Candidate B
     B.1. LASCO  
       #CME 2011/12/25 	18:48:06 UT, partial halo CME (from CDAW)
           

     B.2. STEREO
         Also seen as a CME in COR2-A and COR2 B (first frame at COR2-A 18:54 UT)
         front-side CME, 

     B.3. AIA & GOES
          #GOES 25-Dec-2011 18:11 UT 
          class: M4.0   S22W26  from AR11387 

	
     B.3. Comment
          Could be the source: The timing and orientation is in agreement with the observations
  
   2.2. Comment
        We can observe dimmings for both candidates, but not too extended. 

3. Other Comments

     The active region for Candidate B has different number in GOES and Jhelioviewer. GOES gives it as AR11387, while Jhelioviewer as AR11385. In both cases the location of the active region is the same (SW hemisphere).


     Both candidates can be the source of the ICME, but it is not clear. They occured with some hours difference from different areas. Candidate A is faster than B based on CDAW.

4. Summary
    SW index 2
    Source index 3
    Overall index 3