Category: Ricerca

The relation between stellar metallicity and presence of giant planets in intermediate massive stars described in the study: “Intermediate-mass stars and the origin of the gas-giant planet-metallicity correlation” of J. Maldonado (INAF-OAPA)

Ricerca

As of today (February 2025), out of the 5834 identified exoplanets, only about 5% orbit stars with masses between 1.5 and 3.5 solar masses (intermediate-mass stars). This is likely due to specific difficulties in exoplanet detection techniques, difficulties that are not encountered for lower-mass stars. For example, since they are more luminous than lower-mass stars, the transit depth (i.e., the

» Read more
, , , , , ,

A green monster inside Cas A unveils the secrets of its violent phenomena. The study: “The Green Monster Hiding in Front of Cas A: JWST Reveals a Dense and Dusty Circumstellar Structure Pockmarked by Ejecta Interactions” of I. de Looze (Ghent University) recently appeared on ApJL

Ricerca

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

» Read more
, , , , , , , ,

A sub-neptunian “dynamically hot” orbiting around the star BD+00 444 confirmed with HARPS-N observations.

Ricerca

An intriguing result, obtained thanks to the observational campaign carried out with NASA’s Kepler satellite, is that the most common transiting exoplanets are small planets with a radius smaller than 4 Earth radii and a short orbital period (less than 100 days). In particular, the most frequent planets belong to the sub-Neptune and super-Earth classes, two categories absent in the

» Read more
, , , , ,

First direct detection of relativistic particles accelerated in shocks in the heliosphere described in the study: “Direct Measurements of Synchrotron-emitting Electrons at Near-Sun Shocks” of I. C. Jebaraj (University of Turku)

Ricerca

In the Universe, various environments are characterized by shocks capable of converting the kinetic energy of gas and particle flows into heat, turbulence, magnetic energy, and, ultimately, accelerating particles to relativistic energies, producing cosmic rays. The sizes of these systems can vary by many orders of magnitude, ranging from the typical dimensions of the interplanetary environment to the enormous galaxy

» Read more
, , , ,

Two mini-Neptuns in orbital resonance around TOI-1803 discovered and described in the paper: “A joint effort to discover and characterize two resonant mini Neptunes around TOI-1803 with TESS, HARPS-N and CHEOPS” of T. Zingales (UniPd/INAF-OAPd))

Ricerca

With over 2.600 exoplanets discovered, NASA’s Kepler satellite holds the record for the mission with the highest number of exoplanets found. The Kepler mission continued with the Kepler/K2 extension, redefined after technical failures prevented the telescope from maintaining its pointing. Among the many discoveries made possible by Kepler/K2 is evidence that one of the most common types of planets in

» Read more
, , , , ,

The stellar surface trated as a puzzle. The study: “PAStar: a model for stellar surface from the Sun to active stars” of A. Petralia (INAF – OAPA) appeared on A&A

Ricerca

In stars, a continuous tug-of-war unfolds between stellar plasma and the magnetic field. At stake is control over the local dynamics: the winner sets the rules that govern the local stellar properties. For instance, the photosphere of stars is generally quite homogeneous, except for granulation. However, in certain regions of the photosphere, the magnetic field can concentrate, intensify, and produce

» Read more
, , , , , ,

Non thermal emission and cosmic rays in the supernova remnants SN1006. The paper: “”Hadronic particle acceleration in the supernova remnant SN 1006 as traced by Fermi-LAT observations” of M. Lemoine-Goumard (University of Bordeaux) appeared on A&A

Ricerca

Supernova remnants serve as unique laboratories to understand the complex processes occurring during a supernova explosion and to investigate the internal structure of massive stars just before their explosive demise. Additionally, the study of these remnants is driven by their crucial role in accelerating cosmic rays, which are particles with extremely high energies. In 1949, Enrico Fermi laid the groundwork for

» Read more
, , , , , , , , ,

From Jovian to mini-Neptunian. The evolution of TOI-1430 b described in the study: “The GAPS Programme at TNG. LXV. Precise density measurement of TOI-1430 b, a young planet with an evaporating atmosphere” of D. Nardiello (UniPD, INAF-OAPD)

Ricerca

Young exoplanets, that is, those orbiting stars no older than a few hundred million years, are of significant scientific interest for studying planetary formation and the processes influencing the early evolution of planets. However, the intense magnetic activity of young stars generates signals that can obscure or mimic those linked to the presence of planets, making their detection and characterization

» Read more
, , , ,

(Italiano) Un superammasso stellare svelato dal James Webb Space Telescope. L’articolo: “EWOCS-III: JWST observations of the supermassive star cluster Westerlund 1” di M. G. Guarcello (INAF-OAPA) pubblicato su A&A

Ricerca

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

» Read more
, , , , , , ,

Chronology of a Supernova. The article: “Constraining the CSM structure and progenitor mass-loss history of interacting supernovae through 3D hydrodynamic modeling: The case of SN 2014C” by S. Orlando (INAF-OAPA), published in The Astrophysical Journal

Ricerca

The properties and morphology of supernova remnants result from complex physical processes in the progenitor star, both in the stages preceding the explosion and during the event itself. This involves the rapid collapse of the core, occurring in seconds, up to the shock wave reaching the star’s surface. Additionally, the supernova’s evolution is shaped by interactions between the star’s expelled

» Read more
, , , , ,
1 2 3 4 5 … 31