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Stellar and Galactic physics

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Our galaxy and the magellanic clouds
John Carpenter & Robert Hurt/2MASS Project

The scientific themes of Stellar and Galactic Physics team comprise two aspects: on the one hand the study of the formation, evolution and internal structure of stars and the associated physical and chemical mechanisms, and on the other hand the study of the formation, structure and evolution of our Galaxy and the galaxies of the Local Group.

The team explores the evolution of stars and their associated environment, as well as the physical and chemical mechanisms that drive this evolution. It studies the phases of matter ejection that form circumstellar envelopes, in particular for recently formed hot stars and cold stars at the end of their evolution. The basic processes include stellar oscillation and rotation, magnetic fields, hydrodynamic shocks and flows, the condensation of solid dust, and the emission of various types of radiation. The team is involved in mathematical analysis and numerical modelling. It obtains observations using large observing platforms at visible, infra-red, and radio wavelengths, especially at high temporal, spectral and angular resolution. It also studies the kinematic and chemical structure of the Milky Way Galaxy and nearby galaxies. The goal is to understand how the large structures of the Galaxy (bulge, disc, halo) formed and evolved, and to retrace the history of the formation of stars and of their dynamic evolution within the Galaxy. For this, parameters of large numbers of stars need to be measured, such as their parallaxes and proper movements with Hipparcos, and later with GAIA, as well as the abundances of various key elements (Fe, Li, C, NR, O, Ba, U…) and radial velocities from high-resolution spectra obtained with powerful instruments like UVES and GIRAFFE at the VLT.

Gaia: première image de test

L’image ci-dessous est une image de test du jeune amas globulaire NGC1818 dans le Grand Nuage de Magellan. Cette image a été prise dans le cadre de la phase d’étalonnage du satellite avant le début de la phase scientifique de la mission ; le satellite n’est donc pas encore complètement focalisé ni le mouvement optimisé
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Gaia DR1 : 14th September 2016

2016/09/14. Cette image a été réalisée à partir des données du premier catalogue Gaia : GDR1 ! On y distingue de nombreux objets célestes ainsi que les traces du balayage du ciel effectué par Gaia pendant les 14 premiers mois de la mission. Pour l’astrométrie, cette science des positions et des mouvements des objets célestes, une nouvelle ère débute aujourd’hui. Le 14 septembre 2016 à 12:30, l’Agence Spatiale Européenne (ESA) et le Consortium Européen...
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Rosine Lallement élue à l’Académie des Sciences de Russie

Rosine Lallement est chercheur au CNRS depuis 1986. Elle a travaillé avec trois générations de chercheurs russes (et collabore encore avec les deux plus jeunes) sur l’interaction entre le soleil et le nuage de la Galaxie dans lequel notre étoile se déplace en ce moment.
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Laura Ruiz-Dern’s thesis defense

Supervisors : Carine Babusiaux (Observatoire de Paris) Frédéric Arenou (Observatoire de Paris) The Gaia mission of the European Space Agency (ESA) aims to map our galaxy with an unprecedented astrometric precision. It is therefore very important that the data that will be published be rigorously validated to ensure an optimal quality in the Catalogue. These validations are done by one of the teams of the coordination unit CU9 of the Gaia...
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