To date, April 1st 2024, 74.4% of the 5602 confirmed exoplanets have been discovered through transit observations. This technique involves observing the imperceptible and periodic dimming of the luminosity of the central star during each transit of their planets in front of the star with respect to our line of sight. Furthermore, by comparing spectroscopic observations of the star outside
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One of the lessons we have learned after two decades of exoplanetary science, primarily from the diversity of exoplanets discovered to date, is that various properties of exoplanets depend on the characteristics and evolution of their parent stars. Specifically, stellar X-ray and UV radiation can impact the chemical and physical properties of planetary atmospheres. While UV radiation is primarily absorbed
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Supernova remnants, which are nebulae produced by explosion of supernovae and undergoing rapid expansion, typically serve as intense sources of high-energy radiation, particularly in the form of X-ray emissions. This radiation can be of two different types: thermal and non-thermal. Thermal radiation is emitted by dense material and is contingent upon the temperature of the emitting gas. To emit X-rays,
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Hot Jupiters represent an interesting class of exoplanets that does not exist in the Solar System. These are giant gaseous planets that orbit at such close distances from their stars that their orbital periods are shorter than 10 days. Due to their proximity to their stars, these planets have very hot atmospheres, with temperatures exceeding 1500 K. For this reason,
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The Sun regularly exhibits magnetic phenomena, including sunspots and solar flares, which are not only visually appealing but also crucial for in-depth study and understanding. This is because these phenomena arise from large-scale interactions between the solar magnetic field and its plasma. Moreover, they provide valuable insights into the structure of the Sun and its atmosphere. Almost all other
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Stellar clusters are important targets for studying stellar evolution and, in the case of the youngest star clusters, the products of the star and planet formation processes. Our galaxy hosts a rich population of young stellar clusters, typically with masses of a few hundred solar masses. In the solar neighborhood, for instance, there are only a few young clusters with
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Today in the Milky Way, star formation typically occurs in low-mass environments. Young star clusters (e.g., younger than 10 million years), in fact, typically have a mass of a few hundred solar masses. Nevertheless, our Galaxy hosts a few very massive star-forming regions that can produce tens to hundreds of thousands of stars, including some of the most massive stars
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The formation of stars and planets results from the complex interplay of various factors and agents: the collapse of the cloud due to its own gravitational force, its internal turbulence and magnetic effects, the evolution of star clusters formed within, and the interactions among young stars within these clusters, as well as the influence of their radiation on the surrounding
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Nature sets a lower limit on stellar masses: objects less massive than 0.07-0.08 solar masses are incapable of initiating the thermonuclear reactions that power more massive stars. Below this threshold lies the realm of brown dwarfs, objects whose mass is too small to qualify as stars, yet too large to be categorized as planets. The mechanism responsible for the
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