Note on tracking Sun-Earth connection event

ICME Event: 2011/09/26

Observer: Eleni Nikou on 2019/06

1. ICME
  1.1. Catalog
     # Identified in ICME catalogs: Richardson & Can List
      RC catalog:
      Disturbance start time: 2011/09/26 12:34 UT
      Ejecta      Start time: 2011/09/26 20:00 UT
      Ejecta      End   time: 2011/09/28 15:00 UT
      dv = 130 km/s, v = 580 km/s, vmax= 700 km/s
      MC index:     0
      Dst:        -118 nT
      Suggested source CME: 2011/09/24 12:48 UT
      V_transit:  870 km/s
      
  1.2. Comments
      Overall ICME quality index: 3
      ICME signatures: Bmax: 12.8 nT
               ICME signatures: u decreases smoothly
      
      Disturbance time 580 km/s  -> search window 3 days -> 2011/09/24

2. CME
   2.1. A. Candidate A
    A.1. LASCO:    
      #CME 3011/09/24 09:48 UT, partial halo CME
           

    A.2 .STEREO: 
           Also seen as a CME in COR2-A and COR2 B (first frame at COR2-A 10:24 UT)
	   Front-side CME

    A.3. AIA & GOES    
	   corresponding flare: 24-Sep-2011 09:21 UT 
           class: X1.9  at AR11302, N12E60   

    A.4 Comment:  
	   Could be the source: The timing and orientation is in agreement with the observations.
           We see dimmings on the southern and nothern part of the active region. The active region is close to the eastern limb which means that we can't have a good sight of the dimmings.

   2.1, B, Candidate B
     B.1. LASCO  
       #CME 2011/09/24 12:48 UT, halo CME (from CDAW)
           

     B.2. STEREO
         Also seen as a CME in COR2-A and COR2 B (first frame at COR2-A 13:24 UT)
         front-side CME

     B.3. AIA & GOES
          #GOES flare 24-Sep-2011 12:33 UT
          class: M7.1  at AR11302, N13E45 (the approximation of the location was given by SolarMonitor)

	
     B.3. Comment
          Could be the source: The timing and orientation is in agreement with the observations.
          We see dimmings around the active region. 
  
    2.1, C, Candidate C
      C.1. LASCO  
       #CME 2011/09/24 19:36 UT, halo CME (from CDAW)
           

      C.2. STEREO
         Also seen as a CME in COR2-A and COR2 B (first frame at COR2-A 19:54 UT)
         front-side CME

      C.3. AIA & GOES
          #GOES flare 24-Sep-2011 19:09 UT
          class: M3.0  at AR11302, N13E45 (the approximation of the location was given by SolarMonitor)

	
      C.3. Comment
          It is not the source most probably because of the timining and velocity, it is the slowest candidate.
          Small dimmings at the nothern part of the active region. Part of it is covered by the flare brightenings.

   2.2. Comment


3. Other Comments

     It is not clear which is the candidate, because we had events that occured with a small time difference and there might have been interaction of the multiple ejectas. All of the candidates initiated from the same active region, AR11302. Based on the timing and the velocities, possible candidate is Candidate A. We need to keep in mind though that the disturbance we see in situ could be a result of the multiple ejectas from the same active region. 

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