Tag: brillamenti

Micro-flares and the problem of the coronal heating. The paper: “Coronal energy release by MHD avalanches. Effects on a structured, active region, multi-threaded coronal loop” of G. Cozzo (UNIPA) appeared on A&A

Ricerca

The corona is the outermost part of the Solar atmosphere, filled with plasma at temperatures reaching several million degrees. The mechanism responsible for heating the Solar plasma to these temperatures is a long-standing problem. It began in the 1930s when physicists Bengt Edlen and Walter Grotrian proposed that the mysterious spectroscopic lines observed in the corona were not due to

» Read more
, , , , , , , , , ,

A superflare observed in the M star AD Leo. The study: “The Great Flare of 2021 November 19 on AD Leo. Simultaneous XMM-Newton and TESS observations” of B. Stelzer (Eberhard-Karls-Universität Tübingen) appeared on A&A

Ricerca

Flares are transient and energetic phenomena that occur in most stars and can be observed with high spatial and temporal resolution in the Sun. These phenomena are triggered by a sudden release of energy previously stored in the star’s magnetic field, which, after a sequence of events, leads to extreme heating of the stellar plasma. The heated plasma then rapidly

» Read more
, , , , ,

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

» Read more
, , , , , , , , ,

Flares and variability in DS Tucanae A e AU Mic. The study: “Short-term variability of DS Tucanae A observed with TESS” of S. Colombo (INAF – OAPA) recently appeared on A&A

Ricerca

Stars are variable sources over timescales which depend on the phenomena triggering this variability. These phenomena are typically produced by the interaction between the stellar magnetic field and its plasma. Typical examples, observed and studied in great details in the Sun, are: flares (sudden release of a large amount of energy by the magnetic field which heats the gas in

» Read more
, , , , , , , , ,

The interaction between star and planet triggers more energetic flares. The study: “X-ray variability of HD 189733 across eight years of XMM-Newton observations” of I. Pillitteri (INAF – OAPA) recently appeared on A&A

Ricerca

The corona is the outermost part of the atmosphere in stars with intermediate and low mass. In this region, which is extended for several stellar radii, the plasma can reach temperatures of several million degrees, emitting mainly X-ray radiation. The coronal temperature varies over a range of several orders of magnitude as a function of several stellar parameters, such as

» Read more
, , , , , , ,

Magnetic activity in M stars. The study: “The GAPS programme at TNG. XXVI. Magnetic activity in M stars: spectroscopic monitoring of AD Leonis” of C. Di Maio (UNIPA/OAPA) recently appeared on A&A

Ricerca

Stars which are not fully radiative (e.g., less massive than 8 solar masses) produce a magnetic field in their interior whose intensity and topology depends on the type of star and internal structure. The magnetic field is then drag toward the surface and here it interacts with the plasma in the photosphere, chromosphere, and corona triggering phenomena classified as “magnetic

» Read more
, , , ,

Pulsations in the solar corona. The study: “Large-amplitude quasi-periodic pulsations as evidence of impulsive heating in hot transient loop systems detected in the EUV with SDO/AIA” of F. Reale (UNIPA/INAF-OAPA) recently appeared on ApJ

Ricerca

Solar corona is made of plasma at million degrees. The mechanism responsible for the heating of the corona, which is the outer part of the solar atmosphere, is still one of the unsolved problems of solar physics. For comparison, the plasma in the photosphere is on average at about 5600 degrees. It is widely accepted that the responsible for heating

» Read more
, , , , , , , , ,

Impulsive heating of plasma in coronal loops. The study: “Impulsive coronal heating from large-scale magnetic rearrangements: from IRIS to SDO/AIA” of F. Reale (UNIPA/OAPA) recently appeared on ApJ

Ricerca

The Solar corona is visible in the energetic bands of the electromagnetic spectrum as composed by magnetic arcs filled by plasma at million degrees, which are particularly bright in the active regions. Despite it is clear that the magnetic field plays a fundamental role in heating and confining the plasma, the Solar corona is still a complex region where energetic

» Read more
, , , ,

Super-flares in the Pleiades. The study: “Simultaneous Kepler/K2 and XMM-Newton observations of superflares in the Pleiades” of M. G. Guarcello (INAF-OAPA) recently appeared on A&A

Ricerca

Observations of the Sun show that our star hosts transient and violent phenomena which are due to the interaction between the plasma and the magnetic field produced in the interior of the Sun. Typical examples of this “magnetic activity” are the sunspots in the photosphere and the protuberances in the chromosphere. The solar flares are among those phenomena associated with

» Read more
, , , , , ,

Nanoflares and the heating of solar corona. The study: “Statistical Signatures of Nanoflare Activity. I. Monte Carlo Simulations and Parameter-space Exploration” of D. B. Jess (Queen’s University Belfast) recently appeared on ApJ.

Ricerca

There are still secrets of our Sun that the scientific community struggles to unveil. One of this is the mechanism responsible for the heating of solar corona. While the photospheric plasma has a typical temperature of about 5700 degrees, in fact, the plasma in the solar chromosphere and corona is hotter: about 10000 degrees in the chromosphere and 1-2 millions

» Read more
, , , , , , ,
1 2