Tag: esopianeti

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

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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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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

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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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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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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

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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

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Photoevaporation in young planets. The study: “New Constraints on the Future Evaporation of the Young Exoplanets in the V1298 Tau System” of A. Maggio (INAF – OAPA) recently appeared on ApJ

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The search for young exoplanets is crucial to our understanding of the planetary formation process and the early evolution of planets. The disc of gas and dust from which planets form, in fact, typically disperse in a few million of years. Before that, the young planets interact with all the material orbiting around the star within the disk, triggering important

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As X/UV radiation affects the chemistry of planetary atmosphere. The study: “Extreme-ultraviolet- and X-Ray-driven Photochemistry of Gaseous Exoplanets” of D. Locci (INAF – OAPA) recently appeared on PSJ

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Some of the 4903 exoplanets discovered and confirmed so far (https://exoplanets.nasa.gov/) orbit very close to their stars. We learnt with the very first planet discovered around a star different than the Sun (51 Pegasi b, discovered in 1995) that planets with very close orbits are possible in nature. 51 Pegasi b, in fact, orbits at about 0.05 Astronomical Units (AU,

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Discovered the first planetary system with planets both in equatorial and polar orbits revealed by the study: “The Rossiter-McLaughlin effect revolutions: an ultra-short period planet and a warm mini-Neptune on perpendicular orbits” of V. Bourrier (Observatoire Astronomique de l’Université de Genève), appeared on A&A

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The study of the architecture of planetary systems, and in particular that of the spin-orbit angle (which is the inclination of the planetary orbit with respect to the stellar rotation axis) can unveil important details on the dynamical evolution of planetary systems. In particular, young planets typically migrate radially, changing their distance to the host star and interacting with the

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The study: “Estimating Magnetic Filling Factors from Simultaneous Spectroscopy and Photometry: Disentangling Spots, Plage, and Network” of T. W. Milbourne (Harvard University), recently appeared on ApJ, present two new methods that allow astronomers to estimate the filling factor of magnetic active regions

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About 20% of the exoplanets discovered so far (October 2021) were found with measurements of radial velocity (data from https://exoplanets.nasa.gov/). This method is based on spectroscopic observations of stars with planets, from which it is possible to measure the Doppler effect produced by periodic oscillations of the star, due to the gravitational attraction between star and planet along the orbit of

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The hot Jupiter WASP-33b targeted by HARPS-N. The study: “The GAPS Programme at TNG. XXXI. The WASP-33 system revisited with HARPS-N” of F. Borsa (INAF – AO of Brera) recently appeared on A&A

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Hot Jupiters are gaseous giant planets that orbit very close to their stars (within a typical distance of less than 0.1 Astronomical Units, AU, where 1 AU is the average distance between Earth and Sun, about 150 million of km). These planets are of great interest for astronomers both because of the effects due to the intense incident stellar radiation,

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A super-Earth for the star GJ 9689. The study: “HADES RV programme with HARPS-N at TNG. XIV. A candidate super-Earth orbiting the M-dwarf GJ 9689 with a period close to half the stellar rotation period” of J. Maldonado (INAF-OAPA) recently appeared on A&A

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M stars are the most common stars in the Universe. They have a mass ranging between 0.6 and 0.08 Solar masses in the main sequence, and an effective temperature ranging between 3900 K and 2400 K. In these stars, the signals due to the presence of planets, such as radial velocity (periodic oscillations of the star from its rest position

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