A possible E-W asymmetry of the coronal emission line intensities and K-corona brightness

Abstract

The analysis of the daily measurements of the coronal green and red line intensities as well as the K-corona brightness, which have been collected by the Pic-du-Midi Observatory, for the time period 1944-1974, has revealed some very interesting features. North-South (N-S) asymmetries for all these coronal intensities are confirmed again for this time period. The main point of this analysis is a strong evidence of longitudinal distribution of the coronal intensities as derived from the data record. In our effort to confirm this asymmetry, we have examined the yearly and monthly distribution of the asymmetry coefficient in each solar quadrant showing that the northeast (NE) quadrant appears the most active of all. We have also examined the intensity ratios measured at the East and West solar limbs which is continuously greater than the unit. A seasonal variation of this ratio has also been reported with a maximum during the winter period and a minimum during the summer period. © 1994 Kluwer Academic Publishers