Estudo sobre as variações no raio solar utilizando o HMI/SDO

Abstract

The techniques of observing and measuring the solar radius have evolved throughout the history of scientific evolution. Nowadays, the most reliable methods of measuring the solar radius are the techniques in which the influence of the terrestrial atmosphere (seeing effect) in the measurements of the radius is eliminated. In this regard, space satellites are exceptional. The data of the solar radius obtained by the instrument Heliosismic and Magnetic Imager (HMI) onboard the space telescope Solar Dynamics Observatory (SDO) were used in this work to verify if the solar radius has varied in the analyzed period (2013 to 2019). The temperature data on the HMI instrument was also used to build an empirical model to verify the influence of the temperature of the instruments on the solar radius measurements. With the model, we find the maximum value for the variability in the solar radius in the analyzed period of Δ𝑅 ⊙𝑀É𝐷𝐼𝑂 = 40 𝑚𝑎𝑠