Abstracts submitted by Giannina Poletto
Repetitive ejections from the same source region
A. Bemporad[1], G. Poletto[1], M. Romoli[2], F. Landini[2]
[1]INAF - Arcetry Astrophysical Observatory, Firenze, Italy; [2]Dept. of Astronomy and Space Science, University of Firenze, Italy
On May 28, 2004, the LASCO CME catalog lists five CMEs, two of them originating at the east limb of the Sun at a south latitude of ~ 20 degrees. Ulysses, at the time, was at 5.4 AU at a southern latitude of ~ 5 degrees, off the East limb of the Sun: i.e., at a position where its in situ experiments may possibly detect the CME ejecta. This prompted our interest in the events, which have been observed also by EIT, UVCS and LASCO on SOHO.
Analysis of data from these instruments allowed us to identify the source region of the CMEs in an active region (AR) crossing the solar limb on that day. Spectra taken by UVCS at an altitude of 1.55 solar radii show that at least one further, smaller,ejection originated from the same AR. In spite of their common origin, however, the ejections have different characteristics and different outward speeds. We give here their physical parameters, illustrate the scenario we propose for their origin and comment on the reconnection phenomena associated with the events. |
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