Archives Séminaires 2018-2019

Séminaire

Séminaire IPAG de Fabien Louvet (Université du Chili), jeudi 24 janvier 2019 à 11h00, salle Manuel Forestini

Star formation is a key astrophysical process. At small scale, it governs the settling of planetary systems, and the complex chemistry allowing the emergence of life. At large scale, star formation controls the energy budget of galaxies. Our knowledge about star formation is both extensive and extremely coarse. In the one hand, we know well the different steps that lead from a molecular cloud to a single star, but in the other hand, the physical processes behind those steps are, at best, (...)

Séminaire

Séminaire IPAG de Alexis Coleiro (APC), jeudi 17 janvier 2019 à 11h00, salle Manuel Forestini

The recent detection of high-energy astrophysical neutrinos and gravitational waves open a new era in multimessenger astronomy. Exploring high-energy sources with these new messengers and electromagnetic radiation provides new insights into the physical processes at work in the close environment of compact objects. In this talk, I will address the scientific motivation to search for high-energy neutrinos and their connection with cosmic rays. The challenges of their detection will be (...)

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Séminaire IPAG de Markus Janson (Stockholm University), jeudi 10 janvier 2019 à 11h00, salle Manuel Forestini

Recent scientific advances have revealed a rich set of architectural configurations among stellar/planetary systems. Studying the statistics, physical properties, and orbits of such systems provides clues about their formation and early evolution. Their orbits can also yield dynamical masses which are otherwise unattainable, and which are crucial for purposes such as calibration of theoretical stellar and planetary mass-luminosity relationships, or constraining the ages of young regions. (...)

Séminaire

Séminaire IPAG de Ana Lopez-Sepulcre (IRAM), jeudi 13 décembre 2018 à 11h00, salle Manuel Forestini

The early stages of star formation are characterised by a rich molecular chemistry that can vary substantially from one object to another. Many efforts have been devoted in the past couple of decades to understand the physics and chemistry behind the molecular composition of solar-type protostars. Interestingly, when it comes to organic molecules, two distinct kinds of protostars can be identified : (1) hot corinos, which are small (<100 AU), dense objects where saturated complex organic (...)

Séminaire spécial

Séminaire IPAG de Thierry Montmerle (IAP), mardi 4 décembre 2018 à 13h30, salle Manuel Forestini

The origin of the arc-shaped Sh 2-296 "Seagull" nebula is still mysterious. Some authors have proposed that it is a 0.5 Myr-old supernova remnant (SNR) shock, inducing star formation in the CMa OB1 association. We show instead that the nebula is part of a large, shell-like structure ( 60 pc), enclosing a bubble created by three successive supernova explosions having taken place 6, 2 and 1 Myr ago. We base this chronology on three runaway stars that appear to have been ejected from a (...)

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Séminaire IPAG de Alvaro Hacar Gonzalez (Leiden Observatory), jeudi 29 novembre 2018 à 11h00, salle Manuel Forestini

As demonstrated by different galactic surveys, the star-formation process is intimately connected to the formation and evolution of filaments. Using large-scale observations from both single-dish and interferometers such as IRAM and ALMA, we carried out a systematic study of the molecular emission of several filamentary clouds like Taurus, Perseus, and Orion. The analysis of the internal gas kinematics of these regions indicates a complex substructure in both low- and high-mass filaments. (...)

Séminaire

Séminaire IPAG de Ewine van Dishoeck (Leiden Observatory), jeudi 22 novembre 2018 à 11h00, salle Manuel Forestini

Protoplanetary disks are the birthplaces of planets but the spatial resolution at long wavelengths has so far been insufficient to resolve the critical 5-30 AU region. The Atacama Large Millimeter/submillimeter Array (ALMA) now allows us to zoom in to nearby disks and determine the physical and chemical structure associated with planet formation. This talk will provide examples of recent work on observations and models of protoplanetary disks in various stages of evolution. Young disks like (...)

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Séminaire IPAG de Pierre-Olivier Lagage (CEA Saclay), jeudi 15 novembre 2018 à 11h00, salle Manuel Forestini

The last twenty five years have witnessed an exceptionally fast development in the field of exoplanets. About 4000 exoplanets have been detected so far. While the detection of exoplanets will remain an important field of activity, another chapter is in rapid development : the characterization of their atmosphere.
In this seminar, I will draw the state of the art and the perspectives in the domain. Thanks to its large collective area and its suite of instruments covering a wide range of (...)

Séminaire

Séminaire IPAG de Laurent Pagani (LERMA), jeudi 8 novembre 2018 à 11h00, salle Manuel Forestini

Orion KL is the closest (400 pc) of all the massive star forming regions and allows therefore detailed studies. Despite its closeness, its complexity still calls for interferometric observations in order to separate the different subregions emitting at different velocities, which are otherwise mixed in an inextricable combination of different species at similar apparent frequencies in single dish observations. Orion KL has another peculiarity : it has undergone an explosive event 500 years (...)

Séminaire

Séminaire IPAG de Sylvestre Lacour (LESIA), jeudi 18 octobre 2018 à 11h00, salle Manuel Forestini

PicSat is a space mission which goal was to monitor the Beta Pictoris system. The scientific objective was to observe the Hill’s sphere transit of the Beta Pictoris b planet. The mission has also a technical objective, to inject star light into a single mode fiber. The satellite was successfully launched on a 505 km orbit on January 2018, slightly behind schedule. First contact was obtained within hours, and commissioning of the sub-systems was still ongoing when the satellite fell silent, (...)