Prominence eruptions and coronal mass ejection: A statistical study using microwave observations

We present the results of a statistical study of a large number of solar prominence events (PEs) observed by the Nobeyama Radioheliograph. We studied the association rate, relative timing, and spatial correspondence between PEs and coronal mass ejections (CMEs). We classified the PEs as radial and transverse, depending on whether the prominence moved predominantly in the radial or horizontal direction. The radial events were faster and attained a larger height above the solar surface than the transverse events. Out of the 186 events studied, 152 (82%) were radial events, while only 34 (18%) were transverse events. Comparison with white-light CME data revealed that 134 (72%) PEs were clearly associated with CMEs. We compare our results with those of other studies involving PEs and white-light CMEs in order to address the controversy in the rate of association between CMEs and prominence eruptions. We also studied the temporal and spatial relationship between prominence and CME events. The CMEs and PEs seem to start roughly at the same time. There was no solar cycle dependence of the temporal relationship. The spatial relationship was, however, solar cycle dependent. During the solar minimum, the central position angle of the CMEs had a tendency to be offset closer to the equator as compared to that of the PE, while no such effect was seen during solar maximum.