| Direct Image | Subtraction Image |
|---|---|
![[Direct Image]](http://download.hao.ucar.edu/d5/events/mk3/1998/98d053/
98d053.17_38.ch0.rpB.slit.gif)
|
![[Subt. Image]](http://download.hao.ucar.edu/d5/events/mk3/1998/98d053/
98d053.17_38.ch0.rpB.slit.subt.gif)
|
| 17:38 UT | 17:38 minus 19:01 |
This event was in progress at the beginning of the observing day at Mauna
Loa, approximately 17:39 UT. Close examination of the subtraction images
uncovered what appeared to be a double loop strucutre. There appeared to be
a very faint outer loop encircled by a brighter inner-loop. This
inner-loop was followed in the trajectory measurements because of it's
brightness and clarity. The dim, outer loop could not be followed reliably
in MK3 and was not visible at all in the
LASCO
C2 and C3 fields of view.
The CME appeared in LASCO C2 at approximately 17:55 UT at 2.5 solar radii,
which matched favorably with the MK3 trajectory. The CORE material, appearing
in LASCO C2 at approximately 20:55 UT, was tracked out to about 15 solar radii.
The acceleration fit looked as if it would have better fit a cubic (or
non-constant acceleration fit), rather than the quadratic, constant acceleration
fit used. The loop structure was very diffuse in MK3, C2, and C3 fields of
view, so there is limited confidence in the trajectory measurements of the LOOP
and CAVITY. The CORE feature, however, was bright and easily identified
throughout event, so the measurements made of this feature have the most
confidence. These uncertainties were incorporated into the final fit.
In the LASCO movies of this event, there is a blast of material at the
beginning of the day. This material is not part of the MK3 CME, at least
there is no MK3 counterpart to this material. The CME of interest occurs
later in the day, around 20:55 UT.
Here are the preliminary LASCO notes for this event.
There is a MK3 direct-image movie [GIF, 873K] and a MK3 subtraction movie [GIF, 739K] to view for this event.
There is also a LASCO C2 movie [MPEG, 324 KB] and a LASCO C3 movie [MPEG, 426 KB] of this event as well.
There were a total of 59 data points obtained for use in trajectory fits.
Of those, 7 were for the outer loop, 19 for the cavity, and 33 for the core
feature.
The event times were from 17:39UT (in progress)
until 07:38 UT the following day.
The event was visible in MK3 and continued past the LASCO C3 field of view.
Central Position Angle: ~81 - Loop (in degrees) ~79 - Cavity ~80 - CoreThe following data is obtained from performing a second order, least squares fit of the trajectory data points (Hundhausen, et al, 1994) :
Width (degrees): ~35 - Loop (MK3) ~29 - Cavity (MK3) ~26 - Core (MK3)
Start Times (UT): 16:54:14 - Loop 16:48:25 - Cavity 13:05:19 - Core Start Heights (Solar Radii): 1.0 - Loop 1.0 - Cavity 1.0 - Core Final Speeds (km/s): 115.8 - Loop 65.5 - Cavity 139.6 - Core Accelerations (km/s^2): -0.03 - Loop (out to C2, 7 datapts.) -0.02 - Cavity (out to C2) 0.003 - CoreThe 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.
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, 873 KB]
MK3 images :
Best MK3 Subtraction Images
MK3 movie [GIF, 739 KB]
MK3 images :
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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