Oral comunication
S. L. L. Bourgeois, S. Chierichini, S. Soós, R. Erdelyi, J. Liu, M. B. Korsós, R. Gafeira, T. Barata
Abstract
Investigating coronal structures, such as prominences, solar jets, coronal loops, etc. is essential for understanding their characteristics and how they reveal the magnetic field dynamics within the corona, potentially leading to space weather events. Thus, our goal is to detect these coronal structures and conduct a statistical analysis of their properties, focusing specifically on their density and intensity variations across time, latitude, and longitude throughout Solar Cycle (SC) 24.
In this study, we identify coronal off-limb structures using mathematical morphology algorithms. The original data acquired by the Atmospheric Imaging Assembly (AIA) instrument in the 304 Å channel aboard the Solar Dynamics Observatory (SDO), was pre-processed by Liu et al. (2023, ApJS 266 17) to highlight coronal features. Spanning nearly an entire solar cycle from June 2010 to December 2021 with a 3-hour cadence, the dataset was refined by eliminating noisy or misaligned images, resulting in 32,985 retained images and uncovering a total of 877,843 coronal off-limb structures.
With this extensive dataset, we observed different trends in the distribution of coronal structures between high intensity and lower intensity (corrections were made for the CCD degradation’s impact on the AIA instrument). Specifically, we found that only high-intensity structures follow distinctly the butterfly diagram, whereas lower-intensity structures are more prevalent around the poles and during the declining phase of SC 24. The latitudinal distribution of coronal off-limb structures also shows a North-South asymmetry that varies over years and months. This asymmetry is pronounced in the “rush-to-the-poles” phenomenon, where high-latitude coronal structures from both hemispheres migrate towards the poles before the polar field reversal near the solar cycle maximum. Furthermore, the longitudinal distribution of coronal off-limb structures reveals the presence of active longitudes—longitudinal zones characterized by increased activity. Our analysis also suggests that the positioning of these active longitudes is influenced by latitude and differential rotation.
ESWW2024
Coimbra, Portugal
2024 November
