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 nuova stima della funzione di massa nell’ammasso Trumpler 14 suggerisce una diversa efficienza nella formazione delle nane brune Quando un ammasso stellare si forma in seguito alla contrazione gravitazionale di una nebulosa, la massa delle giovani stelle non è distribuita casualmente, ma segue una funzione analitica nota come “funzione iniziale di massa” (IMF). Una caratteristica interessante dell’IMF è
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Spesso è difficile stabilire se attorno a una stella orbiti un pianeta gassoso, una nana bruna o una stella di piccola massa. Tuttavia, una tecnica che combina misure di velocità radiale e astrometriche può fornire indicazioni affidabili in merito. Alcuni studi condotti su campioni di stelle con esopianeti indicano che, attorno a stelle di tipo solare, la probabilità di
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A new study on the low mass stellar population of the star forming region Corona Australis shed light on the formation of brown dwarfs In recent years, several studies of star-forming regions near the Sun have revealed that a significant fraction of the stellar population of the Milky Way consists of brown dwarfs—objects whose cores do not reach the
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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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Understanding the star formation process also means acquiring a full understanding of its final products, such as the mass distribution of the stars formed in a single star-formation event (which is the initial mass function). In particular, it is still not clear what the dominant mechanism responsible for the formation of the less massive sources is: the planetary-mass objects, with
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Typically, planets did not form at the distance from their central stars where we observe them today. In fact, during their early evolution, planets migrate from their initial orbit until the system reaches its final configuration. Planetary migration can be induced by several processes: the interaction between the newborn planets and the protoplanetary disk where they formed, the gravitational interaction
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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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The James Webb Telescope (JWST) will be the most complex and powerful telescope ever launched into space. Built by a consortium formed by NASA, ESA, and the Canadian Space Agency (CSA), thanks to its primary mirror with a diameter of 6.5 meters (for comparison, the mirror of the Hubble Space Telescope has a diameter of 2.5 meters) and its four
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