Archives Séminaires 2013-2014

Séminaire

Séminaire IPAG de Thomas Gastine (MPIS), jeudi 28 novembre 2013 à 11h00, IPAG seminar room

The magnetic fields of planets and rapidly rotating stars are thought to be maintained by convection-driven dynamos operating in their interiors. Asymptotic scaling laws recently derived from geodynamo-like numerical models successfully predict the magnetic field strength of a wide range of astrophysical objects encompassing Earth, Jupiter and some rapidly-rotating stars. This emphasises the possible similarities between the dynamo mechanisms at work in planets and active M dwarfs.
Recent (…)

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Séminaire IPAG de Joshua Schlieder (MPIA), jeudi 5 décembre 2013 à 11h00, IPAG seminar room

The census of young, M dwarfs in the solar neighborhood is incomplete. Many constituents of the known sample are members of nearby, young moving groups (NYMGs) ; loose associations of coeval stars with common Galactic kinematics. By mining astrometric and photometric catalogs, new candidates of this under-sampled population can be found via their possible association with NYMGs. We have therefore launched the Cool Astrometrically Selected Targets Optimal For Follow-up Spectroscopy (CASTOFFS) (…)

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Séminaire IPAG de Andreas Schruba (IRAM), jeudi 12 décembre 2013 à 11h00, IPAG seminar room

Remarkable progress has been achieved in recent years in quantifying the molecular, atomic and dusty properties of the interstellar medium (ISM) and their relation to star formation in nearby galaxies. This is mainly thanks to a number of dedicated multi-wavelength surveys. For the ISM these include the VLA THINGS and IRAM 30m HERACLES surveys which provide a rigorous view on the atomic and molecular ISM on kiloparsec scales across 50 nearby spiral and dwarf galaxies. I will highlight and (…)

Séminaire exceptionnel

Séminaire IPAG de Laurent Pueyo (STScI), vendredi 20 décembre 2013 à 10h30, IPAG Vercors room

Direct imaging mitigates selection effects inherent to the currently known exo-planetary population, since it is sensitive to objects in an orbital space orthogonal to the one available with indirect methods. Upcoming campaigns will alleviate this selection effect by surveying young and adolescent stars and use high-contrast instruments to direct probe for signatures of their formation history. In this presentation I will discuss the wealth of astrophysical information accessible using such (…)

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Séminaire IPAG de Tiel Birnstiel (CfA, Harvard), jeudi 9 janvier 2014 à 11h00, IPAG seminar room

Dust represents only a small mass fraction of protoplanetary disks, but it is a key player in determining the physical structure and observational appearance of disks and after all, it is the material out of which terrestrial planets and the cores of giant planets are made. In this talk I will present some recent insights to dust evolution in protoplanetary disks and how we plan to find the fingerprints of planetesimal and planet formation by comparisons of theoretical predictions to (…)

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Séminaire IPAG de Nadia Baluccani (Perugia University), jeudi 16 janvier 2014 à 11h00, IPAG seminar room

Complex polyatomic molecules have been observed in a wide variety of extraterrestrial objects (including interstellar clouds, comets and planetary atmospheres) where the physical conditions vary widely. A thorough characterization of the chemical evolution of those objects relies on a multi-disciplinary approach : 1) observations allow us to identify the molecules and their number densities as they currently are ; 2) the chemistry which lies behind their formation starting from atoms and (…)

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Séminaire IPAG de Thibault Cavalie (Bordeaux Obs.), jeudi 23 janvier 2014 à 11h00, IPAG seminar room

As of today, more than 1000 exoplanets have been discovered. The variety of the systems unveiled raises the question of their formation. Because giant planets form faster than terrestrial planets and shape planetary systems, the study of their formation and evolution is of prime interest. The Solar System is our only local laboratory. It is therefore crucial to study in depth how the Solar System formed and works to better understand extrasolar systems Measuring the internal composition of (…)

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Séminaire IPAG de Ferreol Soulez (CRAL), jeudi 30 janvier 2014 à 11h00, IPAG seminar room

Most second generation instruments for the VLT (KMOS, MUSE, SPHERE) and the VLTI (MATISSE, GRAVITY) produce hyperspectral data cube. Surprisingly, only few signal processing methods are dedicated to such data. In my talk, I will present recent advances in hyperspectral signal processing for restoration (deconvolution) in integral field spectroscopy and image reconstruction in polychromatic interferometry. I will show that, with a careful and physically based processing, it is possible to (…)

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Séminaire IPAG de Nicolas Crouzet (STScI), jeudi 6 février 2014 à 11h00, IPAG seminar room

Spectroscopy during transits and eclipses is a very powerful method to probe the atmosphere of exoplanets. Crucial properties such as the molecular composition, the presence of clouds, and the pressure-temperature profile can be derived. Some of the very first exoplanet spectra were obtained using NICMOS onboard HST. Features were identified in the spectra of several hot-Jupiters and attributed to molecular species in their atmosphere. However, these breakthrough discoveries have been (…)

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Séminaire IPAG de Frederic Merlin (Université Paris 7 (Denis Diderot), jeudi 13 février 2014 à 11h00, IPAG seminar room

Ices, and especially water ice, are ubiquitous in the universe. Ices made up of other moderately volatile substances in the outer solar system are known or presumed to exist, for example, on Europa, Ganymede and Callisto (NH3), Titan (CH4 and other carbohydrates), Triton and Pluto (N2, CH4, C2H6), on the surface of the major Saturnian satellites, (CO2, CH3OH, NH3OH), or on Charon (NH3OH). From all these observations we can enumerate several icy species present in the solar system that are (…)