Tag: HARPS-N

A sub-Neptunian exoplanet around the star GJ 720 A. The study: “HADES RV Programme with HARPS-N at TNG XIII. A sub-Neptune around the M dwarf GJ 720 A” of E. González-Álvarez (CSIC-INTA) recently appeared on A&A

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About 19.3% of the 4001 exoplanets confirmed to date were discovered with the technique of the radial velocity (from https://exoplanets.nasa.gov/). This method consists in using time series of spectroscopic observations in order to measure the periodic oscillations of the position of stars due to the presence of orbiting exoplanets. In fact, in a planetary system both the planets and the

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A super-Earth for the star GJ 740. The study: “A super-Earth on a close-in orbit around the M1V star GJ 740. A HADES and CARMENES collaboration” of B. Toledo-Padrón (IAC) recently appeared on Astronomy & Astrophysics

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In the last years, stars of spectral class M (which are stars with effective temperatures between 2400 and 3700 K and masses between 0.08 and 0.45 solar masses) have been extensively observed for the search of exoplanets. This both because they are the most abundant class of stars in the Galaxy, and because the low star/planet mass ratio, compared to

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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

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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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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

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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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Planets with ultra-short period. The study: “An ultra-short period rocky super-Earth orbiting the G2-star HD 80653” of G. Frustagli (INAF – Astronomical Observatory of Brera) recently appeared on A&A

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The “Ultra-Short Period” (USP) exoplanets have very close orbits and orbital periods shorter than one day. These planets typically have a radius smaller than 2 Earth radii and a terrestrial composition, sometime with an excess of iron.   Four hypotheses have been made to explain the formation and evolution of USP planets. The main hypothesis is that these planets originate

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A new super-Earth around an M star. The study: “HADES RV program with HARPS-N at the TNG. IX: A super-Earth around the M dwarf Gl 686” of L. Affer (INAF-OAPA) recently appeared on A&A

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Low mass star (in particular M-type star, with a mass between 0.075 and 0.5 solar masses) are typical targets for the search and study of exoplanets. In these stars, in fact, the radial velocity method is more efficient than in stars with higher mass. Radial velocity consists in detecting periodic oscillations in the stellar spectra due to the motion of

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Planets migrations and impacts. The study: “A giant impact as the likely origin of different twins in the Kepler-107 exoplanet system” of A. S. Bonomo (INAF– OA di Torino) recently appeared on Nature Astronomy

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Exoplanets with a radius smaller than 3 Earth radii span a wide range of characteristics. In fact, both low density sub-Neptunian and high-density Earth- and Mercury-like planets have been observed with such a radius. This diversity suggests that these planets, despite being formed in a similar way, followed different evolutionary patterns depending on the characteristics of their host stars, the

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Three super-Earth for a star. The study “Masses and radii for the three super-Earths orbiting GJ 9827, and implications for the composition of small exoplanets” of K. Rice (University of Edinburgh) published by MNRAS

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Super-Earths are exoplanets with radii between that of the Earth and that of Neptune (about 4 times the radius of the Earth), and with orbital periods smaller than 100 days. Although the Solar System does not host a similar planet, super-Earths are actually common in the Milky Way. This type of exoplanet is also interesting since they populate a gap

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Planets in binary systems. The study: “The HADES RV Programme with HARPS-N@TNG VIII. Gl15A: A multiple wide planetary system sculpted by binary interaction” of M. Pinamonti (INAF-OATo) published on A&A

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In our Galaxy, a large fraction of stars is part of binary systems. For instance, the study of Duquennoy & Mayor (1991) suggests a binary fraction of 57% for solar type stars. A slightly smaller binary fraction is expected for less massive stars. Among pre-Main Sequence stars, several binary systems are known to host a circumbinary disk. These disks are

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A sub-Neptunian planet discovered around a G9 star. Published on MNRAS: “K2-263 b: a 50 d period sub-Neptune with a mass measurement using HARPS-N” of A. Mortier (University of St. Andrews)

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The search of exoplanets relies mainly on two techniques: transits and radial velocity. With the former method exoplanets are revealed thanks to small and periodic dimming of the light of stars when their planets orbit across the stellar disk, producing a small eclipse. The method of radial velocity consists in revealing the oscillations of stars around the center of mass

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