Category: Ricerca

Two bright flares in DS Tuc A and their impact on the nearby planet. The paper: “X-ray flares of the young planet host Ds Tucanae A” of I. Pillitteri recently appeared on A&A

Ricerca

Flares are among the most energetic magnetic phenomena occuring in stars. They are triggered by a sudden release of energy previously stored in the stellar magnetic field, and then they culminate with the formation of magnetic loops in the stellar coronae filled by X-ray and UV emitting plasma at million degrees. Sometimes, these magnetic structures erupt, releasing in the surrounding

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Thermal inversion in the atmosphere of Hot Jupiters. The study: “The GAPS Programme at TNG. XXXIII. HARPS-N detects multiple atomic species in emission from the dayside of KELT-20b” of F. Borsa (INAF – OA Brera) recently appeared on A&A

Ricerca

Thermal inversion is a common phenomenon on Earth’s atmosphere. It occurs when temperature does stop decreasing with increasing height, typically because of layers of warm air flowing upon cold air close to the ground. On Earth, this phenomenon plays an important role in the formation of clouds and precipitation.   Thermal inversion is important also for a peculiar class of

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Howe many planets around M dwarf stars? The study: “HADES RV Programme with HARPS-N at TNG. XV. Planetary occurrence rates around early-M dwarfs” of M. Pinamonti (INAF-OATo) recently appeared on A&A

Ricerca

M dwarf stars, with temperature ranging between 2400 and 3900 K and mass between 0.08 and 0.7 solar masses, are ideal targets for the search of exoplanets. This because the most important techniques to search for exoplanets are more effective when applied to stars of this spectral type than to more massive stars. For instance, the method of radial velocity

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The properties of the reverse shock in Cas A reveal properties of the progenitor. The paper: “Evidence for past interaction with an asymmetric circumstellar shell in the young SNR Cassiopeia A” of S. Orlando (INAF – OAPA) recently appeared on A&A

Ricerca

Supernova remnants (expanding clouds produced by the explosion of massive stars) are fascinating objects. Their study, in fact, can unveil the physical processes working during supernova explosions and even the properties of the stellar progenitors. To these aims, of particular importance is the analysis of the physical and chemical properties of the ejecta (which are the fragments of the dying

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Stellar age and magnetic activity. The study: “The GAPS programme at TNG XXXIV. Activity-rotation, flux–flux relationships, and active-region evolution through stellar age” of J. Maldonado (INAF-OAPA) recently appeared on A&A

Ricerca

Almost all stars in the Universe produce their own magnetic field with a process called stellar dynamo, whose basic ingredients are stellar rotation and convection. In general, magnetic fields are produced and are affected by charged particles, which is what stellar plasma is made of. In stars the magnetic field and plasma thus interact, producing a class of transient phenomena

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A chapter wrote by M. Barbera, U. Lo Cicero and L. Sciortino (INAF-OAPA) on the filters for X-ray telescopes is included in the: “Handbook of X-ray and gamma ray astrophysics”

Ricerca

X-ray astronomy explores the high-energy Universe. X-rays are, in fact, high energy photons emitted by very hot gas (with temperature of some milion degrees) or by processes involving relativistic particles. Some astronomical sources of X-rays radiation are: accreting black holes, such as the supermassive black holes at the center of active galaxies, stellar coronae, supernova remnants, and clusters of galaxies.

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Supernova remnants as particle accelerators. The study: “The supernova remnant SN 1006 as a Galactic particle accelerator” of R. Giuffrida (UniPA/INAF-OAPA) recently appeared on Nature Communication

Ricerca

Our planet is constantly bombarded by energetic particles (mainly protons) called “cosmic rays“. The study of cosmic rays is a leading science topic given its importance in several fields, such as the study of the effects on instrumentation and astronauts in space, where the natural protection against these particles provided by the magnetic field of Earth is low or null.

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A new catalog of the Young Stellar Objects within 4500 light years based on Gaia/EDR3. The study: “Low mass young stars in the Milky Way unveiled by DBSCAN and Gaia EDR3. Mapping the star forming regions within 1.5 Kpc” of L. Prisinzano (INAF – OAPA) recently published by A&A

Ricerca

After their formation, during the first few million of years (how many? it depends on the mass: the larger the stellar mass the faster is their evolution) stars continue to contract under their the action of their own gravity, rising their temperature and density. During this phase, their nuclei have not started yet the thermonuclear reactions that will power the

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Confirmed the existence of a neutron star in the center of SN1987A. The paper: “Additional Evidence for a Pulsar Wind Nebula in the Heart of SN 1987A from Multiepoch X-Ray Data and MHD Modeling” of E. Greco (University of Amsterdam; INAF-OAPA) recently appeared on Apj

Ricerca

SN1987A, the supernova exploded in the Large Magellanic Cloud (at about 170000 light years of distance) on February 23rd 1987, was an iconic event for the study of supernovae and supernova remnants. In fact, it is the only case where it was possible to observe (with telescopes) the explosion and to follow with periodic observations the evolution of the supernova

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