A new theoretical study shows that the holes in the structure observed by the James Webb Space Telescope called “Green Monster” within the Cassiopeia A (Cas A) supernova remnant is due to the interaction between a pre-existing layer of circumstellar material, impacted by the supernova shock wave, and elongated stellar fragments produced by hydrodynamic instabilities. Supernova remnants are objects of
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The star-forming regions can differ significantly from one another, particularly in terms of the population of massive stars (with masses exceeding about 10 solar masses) and stellar density (defined as the number of stars per unit volume). These aspects can vary drastically from one region to another. Such differences are extremely important, as massive stars create environments dominated by high-energy
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The properties and morphology of supernova remnants result from complex physical processes in the progenitor star, both in the stages preceding the explosion and during the event itself. This involves the rapid collapse of the core, occurring in seconds, up to the shock wave reaching the star’s surface. Additionally, the supernova’s evolution is shaped by interactions between the star’s expelled
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The characterization of exoplanetary atmospheres is one of the most active research fields in modern astrophysics, made possible by the development of dedicated instruments and techniques. The basic idea of this research is quite simple: obtaining spectroscopic observations of stars with planets during the transit of the planet in front of its star, which is the moment when part of
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The role of supernova remnants (expanding clouds produced by supernovae) in the acceleration of cosmic rays (high-energy particles present in various astrophysical environments) has been known since 1995. The discovery, made by astronomers from Kyoto University, was made possible by identifying the presence of non-thermal X-ray emission in the supernova remnant SN 1006. X-rays are a type of high-energy radiation
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Massive stars live short and violent lives. Mainly during the later stages of their evolution, these stars undergo significant changes in their structure and lose a large fraction of their initial mass into the surrounding environment as stellar winds. In particular, during the Wolf-Rayet phase, which lasts only a few hundred thousand years, massive stars eject their outer layers, which
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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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