Category: Ricerca

A laboratory experiment to test particle acceleration in astrophysical environments. The study: “Laboratory evidence for proton energization by collisionless shock surfing” of W. Yao and J. Fuchs (École Polytechnique, Sorbonne Université) recently appeared on Nature Physics

Ricerca

Energetic particles, called “cosmic rays”, constantly rain down on our planet. Thanks to several years of theoretical studies and observations, we know that these particles can be accelerated by shocks propagating in certain astrophysical environments. The classical example of such environment are the supernovae remnants, which are expanding clouds created by supernova explosions, which are often interacting with surrounding material.

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The role of the magnetic field during the evolution of supernova remnants i. The study: “Magneto-hydrodynamic simulations of young supernova remnants and their energy-conversion phase” of O. Petruk (IAPMM NASU) recently appeared on MNRAS

Ricerca

Supernova explosions are sorted into two categories: The thermonuclear explosions triggered by white dwarfs in close binary systems (type Ia) and those triggered by the gravitational collapse of the core of massive stars (type Ib/c and II). Because of the paucity of known supernova remnants younger than 1000 years, astronomers developed several models describing the evolution of supernova remnants to

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A comparison between different diagnostics of the age of stellar clusters. The study: “The Gaia-ESO survey: a lithium depletion boundary age for NGC 2232” of A. S. Binks (Keele University) recently appeared on MNRAS

Ricerca

Measuring stellar ages is a difficult task but nevertheless very important. For instance, the study of stellar evolution requires accurate estimate of stellar ages. On the other hand, we can count on very few diagnostics that can allow astronomers to obtain reliable estimate of stellar ages, and typically these methods can be applied only to specific type of stars or

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A rapid dispersion for protoplanetary disks in low metallicity. The study: ” Dispersal timescale of protoplanetary disks in the low-metallicity young cluster Dolidze 25″ of M. G. Guarcello recently appeared on A&A

Ricerca

Protoplanetary disks are disk-like structures that are found in low-mass stars younger than 10 million of years, typically called “pre-main sequence stars”. These disks are also the sites where planets formation occurs. In the last years, scientists have devoted a large effort to study the evolution and dispersion of protoplanetary disks. This has been possible also thanks to facilities such

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A young and low-density planet for DS Tucanae A. The study: “Constraints on the mass and atmospheric composition and evolution of the low-density young planet DS Tuc A b” of S. Benatti (INAF – OAPa) recently appeared on A&A

Ricerca

The study of planets orbiting around young stars (younger than 100 million years) can help astronomers understanding the physical processes setting the early evolution of planetary systems. However, young stars are typically characterized by rapid rotation and intense magnetic activity, phenomena which produce photometric and spectroscopic signals that can mimic and confuse those due to the presence of planets. It

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A sub-Neptunian exoplanet around the star GJ 720 A. The study: “HADES RV Programme with HARPS-N at TNG XIII. A sub-Neptune around the M dwarf GJ 720 A” of E. González-Álvarez (CSIC-INTA) recently appeared on A&A

Ricerca

About 19.3% of the 4001 exoplanets confirmed to date were discovered with the technique of the radial velocity (from https://exoplanets.nasa.gov/). This method consists in using time series of spectroscopic observations in order to measure the periodic oscillations of the position of stars due to the presence of orbiting exoplanets. In fact, in a planetary system both the planets and the

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Jets launched during supernova explosions. The study: “X-ray emitting structures in the Vela SNR: ejecta anisotropies and progenitor stellar wind residuals” of V. Sapienza (UNIPA/OAPA) recently appeared on A&A

Ricerca

Supernova remnants are clouds in rapid expansion formed by supernova explosions. Typically, these remnants are very inhomogeneous. These inhomogeneity is the result of the interaction between the expanding remnant and the surrounding material, and, in particular when they are generated by core-collapse supernova explosions (which are the supernova triggered by the gravitational collapse of the cores of massive stars), also to anisotropies formed

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The interaction between expanding SNR and surrounding clouds. The study: “Modeling the mixed-morphology supernova remnant IC 443. Origin of its complex morphology and X-ray emission” of S. Ustamujic (INAF-OAPA) accepted on A&A

Ricerca

Supernova remnants are clouds in rapid expansion produced by supernova explosions. They are often characterized by a complex morphology, resulting from the interaction between the expanding remnants and surrounding clouds. Supernova remnants also emit radiation on a wide band of the electromagnetic spectrum. This is due to the variety of phenomena occurring in these objects, and because of the different

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The chemical composition of the Hot Jupiter HD 209458b tells us about its history. The study: “Five carbon- and nitrogen-bearing species in a hot giant planet’s atmosphere” of P. Giacobbe (INAF – OATo) recently appeared on Nature

Ricerca

The discovery of the first planet orbiting around another star occurred in the 1995, thanks to the astronomers Michel Mayor and Didier Queloz. This discovery set a milestone in astronomy both because it was the first observational confirmation of the existence of planets orbiting around other stars (in this case 51 Pegasi), and because of the nature of this exoplanet. It

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Composition of a sub-neptunian exoplanet with TESS and ESPRESSO. The study: “A sub-Neptune and a non-transiting Neptune-mass companion unveiled by ESPRESSO around the bright late-F dwarf HD 5278 (TOI-130)” of A. Sozzetti (INAF-OATo) recently appeared on A&A

Ricerca

The NASA satellite Transiting Exoplanet Survey Satellite (TESS) it’s one of the most effective telescopes to search for exoplanets. TESS is designed to find exoplanets with the transits method, e.g. by observing the periodic occultations of stars by their planets during their orbits. To date, about 27% of the exoplanets discovered with TESS belong to the class of the sub-neptunians. These planets have a

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