Grazie al progetto EWOCS, identificata per la prima volta la popolazione di oggetti sub-stellari di un superammasso stellare Attraversando il diagramma di Hertzsprung-Russell dalle masse maggiori a quelle minori, si incontrano stelle con struttura interna, proprietà ed evoluzione totalmente diverse. Il limite inferiore in termini di massa per una stella è di 0.075 masse solari: al di sotto di
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Una ricerca di controparti infrarosse di magnetars con HST e JWST per misurarne la velocità e identificarne il luogo di formazione Le magnetar sono stelle a neutroni caratterizzate da un campo magnetico da 10 a 100 volte più intenso rispetto a quello delle altre stelle a neutroni. L’origine di questo campo magnetico è ancora dibattuta: potrebbe trattarsi di un
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L’evoluzione finale delle stelle massicce presenta ancora diversi punti da chiarire. Sin dal 1975 è stato proposto che le stelle di Wolf-Rayet (WR), stelle di grande massa che hanno espulso i propri strati esterni ricchi di idrogeno ed elio, caratterizzati da temperature elevatissime e venti a migliaia di km/s, siano il prodotto di perdite di massa estremamente intense. Tuttavia, solo stelle con
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Eight free-floating planetary-mass objects, identified in three star-forming regions, exhibit unique features: signs of ongoing planet formation and silicate-rich clouds in their photospheres. It was in the year 2000 that we first learned of the possible existence of free-floating planetary-mass objects—not bound to any exoplanetary system—thanks to observations analyzed by two research groups, one from the Institute of Astrophysics
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Too small to be a star, too large to be a planet, Cha 1107-7626 is the smallest known isolated object (6–10 Jupiter masses) surrounded by a protoplanetary disk rich in gas and dust, which is still actively accreting gas and hosts organic molecules such as methane and ethylene. Brown dwarfs are fascinating objects that represent a bridge between stars
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The James Webb Space Telescope, the flagship observatory of NASA/ESA/CSA, has turned its gaze toward the supernova remnant SN 1987A, revealing its structure with an unprecedented level of detail. About 400 years after Kepler supernova, which exploded in 1604, the skies of the southern hemisphere witnessed another supernova relatively close to us. This was SN 1987A, which exploded on
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A new theoretical study shows that the filamentary structure observed in the supernova remnant Cassiopeia A (Cas A) is a direct consequence of the processes that occurred in the progenitor star immediately after core collapse. Supernovae are among the most energetic explosive events in the Universe. Yet, despite their immense brightness, they convert only about 1% of their energy
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There are many lessons about the physics of supernova remnants and progenitor stars that the Cassiopeia A (Cas A) supernova remnant teaches us. For example, we have learned that both the supernova explosion and the mass-loss episodes that characterize the final evolutionary stages of the progenitor star can be highly asymmetric. We have come to understand that supernovae can play
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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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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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