Analysis of the variation of the apparent radius of the Sun.

Due to the dynamics of its surface, the Sun, our closest star, has been a constant subject of interest throughout the history of astronomy. Observing and analyzing this celestial body has been crucial for understanding not only variations in its apparent size and activity but also its evolution and influence on the solar system. Studying the Sun is essential for deepening our knowledge of its impact on the spatial and planetary environment. This research focuses on the evolution of the solar size from 1980 to 2020. To achieve this, information from the BASS2000 solar database was collected and analyzed, using data obtained from the spectroheliographs of the Meudon and Coimbra observatories. The analysis reveals an apparent solar radius with a peak near 685,000 km and a symmetric distribution. Although linear regression shows a possible upward trend in the Sun’s apparent radius, this should be interpreted with caution due to potential data variations and significant daily variability observed.