MLSO Mark-III K-Coronameter
Coronal Mass Ejection

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8 March 1998 . . . Day of year: 67

Direct ImageSubtraction Image
[Direct Image] [Subt. Image]
19:32 UT19:32 minus 19:00

Event Information

Event Description

In this event, it was difficult to identify the LOOP/CAVITY/CORE features, especially in LASCO C2 and C3 fields of view. No measurements were taken in C3 due to this difficulty. As far as MK3 was concerned, there was an easily identifiable bright feature at the onset of the event which at first appeared to be a core, or prominence material. Later in the event, however, a loop strucutre appears and this bright spot seems to be at the leading edge of it. Therefore, for the purposes of trajectory measurements of this particular event, the leading edge of this bright spot was measured as the leading edge of the LOOP and the trailing edge of this feature was measured as the CAVITY. No CORE measurements were taken. If there is substantial disagreement regarding the identification of features, then we can consider changing them.

Remember, measurements were taken only out to the LASCO C2 field of view. No CME features could be identified in C3 with any confidence.

Here are the preliminary LASCO notes for this event.

There is a MK3 direct-image movie [GIF, 1326K] and a MK3 subtraction movie [GIF, 819K] to view for this event.

There is also a LASCO C2 movie [MPEG, 236 KB] and a LASCO C3 movie [MPEG, 334 KB] of this event as well.

Event Properties

There were a total of 32 data points obtained for use in trajectory fits. Of those, 17 were for the outer loop, 15 for the cavity, and 0 for the core feature.
The event times were from 19:16UT until 20:57 UT The event was visible in MK3 and continued past the LASCO C2 field of view. No identifiable features were found in LASCO C3. 

Central Position Angle:   ~113 - Loop	
   (in degrees)		  ~111 - Cavity 


Width (degrees): 	  ~34  - Loop   (MK3) 
			  ~21  - Cavity (MK3)
The following data is obtained from performing a second order, least squares fit of the trajectory data points (Hundhausen, et al, 1994) : 
Start Times (UT):	  18:42:58 - Loop    
			  19:09:16 - Cavity  

Start Heights (Solar Radii):   1.0 - Loop  
			       1.0 - Cavity 

Final Speeds (km/s):	     301.9 - Loop    (at C2)
			     229.7 - Cavity  (at C2)
				
Accelerations (km/s^2):	      0.02  - Loop    (out to C2)
			     -0.03  - Cavity  (out to C2)
The above numbers were produced from a second-order fit of trajectory data which began in MK3 and ended in LASCO C3. Estimated start times, start heights, final speeds and accelerations are available in each individual data set (MK3, C2, and C3) where enough data points were available. That information is not presented here. Final speeds were evaluated at last data point in C3 except where noted.

Image Gallery

A gallery of the `best' direct and the `best' subtraction images (`display' version) from this event may be accessed below.

Be aware that these are only a few of the images that you may access. For a complete list of images, including the `computational' versions, please visit our FTP site.

All times are given in Universal Time (UT) units.

Best MK3 Direct Images

MK3 movie [GIF, 1326 KB]

MK3 images :

Best MK3 Subtraction Images

MK3 movie [GIF, 819 KB]

MK3 subtraction images :

References 

Hundhausen, A.J., J.T. Burkepile, and O.C. St.Cyr,
  Speeds of coronal mass ejections:  SMM Observations
  from 1980 and 1984-1989,
  J. Geophys. Res., 99, 6543-6552, 1994.

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