Tag: attività stellare

A study on the coronal activity in a complete sample of M stars nearby to the Sun. The paper: “Complete X-ray census of M dwarfs in the solar neighborhood. I. GJ 745 AB: Coronal-hole stars in the 10 pc sample” of M. Caramazza (Eberhard-Karls Universität Tübingen) appeared on A&A

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The corona is the outermost part of the atmosphere of the vast majority of stars, where the plasma is heated to millions of degrees by stellar magnetic activity. Since both the intensity and the topology of the stellar magnetic fields depend on the internal structure of stars, the study of coronal activity allows astronomers to better understand both the high-energy

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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

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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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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

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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

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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

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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

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Variability and magnetic activity in pre-Main Sequence stars. The study: “CSI2264: Simultaneous optical and X-ray variability in the pre-main sequence stars of NGC2264. II: Photometric variability, magnetic activity, and rotation in class III objects and stars with transition disks” of M. G. Guarcello (INAF-OAPA) recently appeared in A&A

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Pre-Main Sequence stars are young stars whose cores are not dense and hot enough to ignite the thermonuclear reactions that will power them for the rest of their evolution. These stars are sorted in three classes: the youngest stars are the class I sources, still embedded in an accreting envelope of gas; class II stars have dispersed their accreting envelope

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Stellar activity suppressed by close-in exoplanets. The study “Suppressed Far-UV Stellar Activity and Low Planetary Mass Loss in the WASP-18 System” of L. Fossati (Space Research Institute – Austria) published by AJ

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All the magnetic phenomena occurring in stars, such as flares and spots, are called “stellar activity”. Astronomers study stellar activity using different diagnostics such as X-ray emission from the coronae and spectroscopic indices like the R’HK measuring the chromospheric activity. This is an important research field in stellar astronomy, given that stellar activity is connected to the intensity and morphology

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A new super-Earth discovered thanks to Harps-N. The study “HADES RV Programme with HARPS-N at TNG. GJ 3942 b behind dominant activity signals” of M. Perger published by A&A

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The analysis of radial velocity is one of the two main methods used to detect exoplanets. This method consists in measuring the Doppler effect on stellar spectra deriving the velocity component along the line of sight (the radial velocity). If the star has a planet, they both orbit around the common center of mass,  producing periodic oscillations of the osberved

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Domenica 7 Maggio Laboratorio Astrokids: “DETECTIVE STELLARI” alla Feltrinelli

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Domenica 7 Maggio alle 11, alla libreria La Feltrinelli, un altro imperdibile appuntamento con il laboratorio Astrokids:”DETECTIVE STELLARI”! Quando una stella muore, gli astrofisici svolgono delle indagini come dei veri detective! Ce lo spiega Salvatore Orlando, astronomo dell’INAF – Osservatorio Astronomico di Palermo (OAPa) insieme ai divulgatori e ai volontari del Servizio Civile Nazionale dell’OAPa. Non mancheranno video, simulazioni, giochi a tema e attività

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Lo studio “HADES RV Programme with HARPS-N at TNG ⋆ III: Flux-flux and activity-rotation relationships of early-M dwarfs” pubblicato su Astronomy & Astrophysics

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Nelle survey dedicate alla ricerca e caratterizzazione di pianeti extrasolari, sono osservate principalmente stelle di piccola massa, come ad esempio nel caso di “HArps-N red Dwarf Exoplanet Survey” (HADES), che vede un forte coinvolgimento dell’Osservatorio Astronomico di Palermo. Le diagnostiche tipicamente usate per individuare pianeti extrasolari possono produrre falsi positivi indotti dall’attività delle stelle osservate, come ad esempio la presenza

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