2024AstBu..79..121S

We present the results of analyzing the activity manifestations of the K3 V spectral type dwarf HIP 113103 (HD 216530) and estimate the the matter loss from the atmospheres of two of its planets. HIP 113103 can be classified as a relatively young object with an age of about 470 million years?1 billion years. Using the standard method, based on the observed data from the TESS mission, we estimated the areas of spots on the surface of the star, which exceed the maximum area of spots on the Sun and are 6100 and 4950 MSH for sectors 1 and 28, respectively. According to the data from the observation archive of the All Sky Automated Survey, the activity cycles of HIP 113103 have been established to last about 610, 825, and 1030 days (1.7, 2.3, and 2.8 years, respectively). Both planets in the stellar system HIP 113103 are characterized as objects with radii of 1.829 R_solar and 2.400 R_solar, with periods of 7.6 and 14.2 days, lying on opposite sides of the Fulton Gap in the ''Period-Radius'' diagram. The loss of matter from the planetary atmospheres was calculated using an approximation formula corresponding to the energy-limited atmospheric loss model.