Hydrogen, helium and sodium in the atmosphere of the Saturnian planet TOI-5398 b

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 Kepler supernova remnant: a cosmic particle accelerator

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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Water vapour or stellar activity? The case of the super-Eart LHS 1140 b

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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Molecules in the atmospheres of exoplanets externally irradiated by UV and X-rays

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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Non thermal X-ray radiation from superfast ejecta in SN 1006

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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SpotCCF, a new tool capable of finding and characterizing spots in active stars.

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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Almost 6000 X-ray sources in the supermassive star cluster Westerlund 1 revealed by the EWOCS project

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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Young stars in massive star-forming regions. The results of the “Chandra Cygnus OB2 Legacy Survey” recently published

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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