O estudo de erupções estelares em aglomerados abertos utilizando curvas de luz TESS

Abstract

Stellar magnetic fields are directly linked to fundamental stellar parameters such as age and mass, and they can give rise to extremely energetic events known as flares. These events correspond to significant explosions that occur on the surface of stars due to variations in the lines of these magnetic fields. The study of these phenomena can provide insights into the behavior of stellar magnetic activity, influencing the space weather in the stellar system’s vicinity, including the atmospheric conditions of nearby planets. In this work, we investigate the activity of these flares in 15 open clusters of different ages, utilizing short-cadence TESS light curves. Our study is based on the analysis of 3892 light curves from 1518 stars, resulting in the identification of 2288 flares. The properties of these flares, such as equivalent duration, and energy in the TESS band, were calculated for each event. The results revealed a decrease in the occurrence of flares with increasing cluster age. Most flares, with 1092 events, were observed in the Pleiades, hundreds of events in the Hyades and α Persei, and a few dozen in Alessi 13, IC 2602, and Praesepe. The observed flares energy varies from 4.154×1032 to 2.892×1035 ergs. No flares were identified in clusters older than one billion years. When comparing Praesepe and Hyades, both approximately 700 million years, significant differences in the frequency of flares were observed. Although flare activity decreases with age, other astrophysical properties, such as variations in periods of high and low magnetic activity, directly influence the flare frequency rate.