Category: Ricerca

Chemical composition and elevation of the atmosphere of WASP-121b. The study: “Atmospheric Rossiter-McLaughlin effect and transmission spectroscopy of WASP-121b with ESPRESSO” of F. Borsa (INAF-OA Brera) recently appeared on A&A)

Ricerca

Ultra-hot Jupiters are gaseous planets orbiting at close distances from their central stars, with rotation periods shorter than 3 days. Their atmospheres are thus heated, more than 2000 degrees, by the incident radiation emitted by the central star. For this reason, the atmospheres of ultra-hot Jupiters shows peculiar properties compared with planets of other types. For instance, they are affected

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Winds and jets from protoplanetary disks. The study: “The Evolution of Disk Winds from a Combined Study of Optical and Infrared Forbidden Lines” of I. Pascucci (The University of Arizona) recently appeared on A&A

Ricerca

The study of protoplanetary disks (which are disks orbiting around young pre-main sequence stars) is of great interest since planets formation occurs in these structures. Disks are dispersed in a few million years (typically less than 10 Myrs) by the planets formation itself, the accretion of material onto the central star, and the loss of material launched in a highly

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The fraction of exoplanets as a function of stellar metallicity. The study: “HADES RV Programme with HARPS-N at TNG XII. The abundance signature of M dwarf stars with planets” of J. Maldonado (INAF-OAPA) recently appeared on A&A

Ricerca

The mechanisms involved in the formation of planets are still not completely understood. The most widely accepted model that describe the formation of gaseous planets is the core-accretion model. In this paradigm, the formation of these planets starts with the formation of a large rocky core by the coagulation of planetesimals, followed by the accretion of a large gaseous envelope

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A study on stellar clusters to calibrate the relation between Lithium abundance and age. The study: “The Gaia-ESO Survey: Calibrating the lithium-age relation with open clusters and associations. I. Cluster age range and initial membership selections” of M. L. Gutiérrez Albarrán (Universidad Complutense de Madrid) recently appeared on A&A

Ricerca

Determining stellar ages can be a difficult task. One of the main difficulties is due to the fact that methods to evaluate stellar ages are specialized for given types of stars and they do not work for the others. Besides, during the longest phase in stellar evolution, the Main Sequence, stellar parameters such as radius and temperature do not change

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An Hot Jupiter that may not be there. The study: “The GAPS Programme at TNG. XXVII. Reassessment of a young planetary system with HARPS-N: is the hot Jupiter V830 Tau b really there?” of M. Damasso (INAF-OATo) recently appeared on A&A

Ricerca

Some of the exoplanets known so far belong to classes that do not exist in our Solar System. For instance,  the class of the Hot Jupiters, i.e., gaseous giant planets orbiting at close distances from their stars (typically less than 0.5 AU, Astronomical Unit, where a 1 AU is the average distance between Sun and Earth, about 150 million km).

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MHD simulations connecting supernova explosions and SNR. The study: “Three-dimensional modeling from the onset of the SN to the full-fledged SNR. Role of an initial ejecta anisotropy on matter mixing” of A. Tutone (UNIPA/INAF-OAPA/INAF-IASF) recently appeared on A&A

Ricerca

Supernova explosions, occurring and the end of the life of massive stars, are ruled by a complex physics, and they can not be described by a simple spherically symmetric geometry. The rarity of these events make even more difficult to understand the physical processes involved during the explosions. For instance, on average only one supernova explodes in our Galaxy every

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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

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

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A super-Earth orbiting around an old M star. The study: “GJ 357 b. A super-Earth orbiting an extremely inactive host star” of Modirrousta-Galian (UNIPA/INAF-OAPA) recently appeared on A&A

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Despite theoretical models predict a large abundance of Earth-like planets in our Galaxy, the family of the 4284 planets discovered so far (updated at 2020/9/25, credits: NASA) counts relatively a few of such a planets. This is clearly an observational bias, due to the fact that the methods used to detect planets are not sensitive to small planets. For this

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Infrared variability in pre-Main Sequence stars. The study: “Near-infrared time-series photometry in the field of Cygnus OB2 association II. Mapping the variability of candidate members” of J. Roquette (University of Exeter/ ICEx – UFMG) recently appeared on A&A

Ricerca

Pre-Main Sequence stars are young stars whose nuclei are still not hot enough to trigger the thermonuclear reactions that will produce energy for the rest of their existence. Some of these stars are called “T Tauri”, and they are surrounded by a protoplanetary disk made of gas and dust, where planetary systems may form. T Tauri stars were classified for

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