In the last few years, many space missions and ground-based surveys, discovered more than 4000 exoplanets, especially using the transit and radial velocity methods. These two methods combined, give us a first estimation of the bulk density of the planets. In order to have a deeper understanding on the planetary characteristics and history, we also need to study their atmospheres.
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In the Milky Way one of the main modes of star formation is in stellar clusters, which remain associated with their parental cloud for about 5-10 million years. This makes the star forming regions complex targets, characterised by rich stellar populations packed into small regions, sometime even with massive stars, and clouds whose morphology and properties are affected by the
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OB associations are groups of massive stars (with spectral type O and B, more massive than 3.5 solar masses) which typically cover wide regions in the sky. The presence of such a rich population of massive stars suggests the presence of even a larger population of low-mass stars. There exists, in fact, a relation between the number of stars in
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di Mario Giuseppe Guarcello ( segui mguarce) Lo studio dei resti di supernova, nubi formate dalle esplosioni di supernova, sono oggetti di grande interesse scientifico. Queste nebulose, infatti, non sono semplicemente il residuo di uno dei fenomeni più violenti che avvengono nell’Universo (un’esplosione di supernova dal collasso di una stella massiva, ossia le “core-collapse supernovae”, produce un’energia pari
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Interstellar and circumstellar dust plays a fundamental role in several astrophysical processes and environments, such as in protoplanetary disks, which are structure orbiting pre-main sequence stars for less than ten million years, and which are the site of planet formation. For instance, despite the mass of protoplanetary disks is dominated by gas (mainly hydrogen), their dust grains are mainly responsible
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A recent study by a team of researchers of INAF-Astronomical Observatory of Palermo, the University of Palermo, and the University of Madrid, recently published on the Astrophysical Journal, shows that enormous flares in the young stars in Orion are due to large magnetic loops connecting the stars and their protoplanetary disks, confining plasma oscillating from disk to the star.
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In the last years the number of known exoplanets has grown quickly thanks to missions such as Kepler and CoRoT and instruments such as HARPS-N, mounted on the Telescopio Nazionale Galileo, which are designed to identify exoplanets with the method of transits or radial velocity. We have understood now that the presence of exoplanets is a common features in stars
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