Archives Séminaires 2015-2016

Séminaire

Séminaire IPAG de Andrew Collier Cameron (St Andrews University), jeudi 24 mars 2016 à 11h00, IPAG seminar room

Hot Jupiters are intrinsically rare objects, but selection effects favour their discovery in both radial-velocity surveys and ground-based transit searches such as WASP and HAT. I will discuss the migration routes that bring these gas-giant planets into such close orbits around their host stars. I will then examine the environmental factors that determine the long-term survival prospects of hot Jupiters, showing how tides and irradiation sculpt the inner boundary of the mass-separation (…)

Séminaire

Séminaire IPAG de Susmita Chakravorty (IPAG), jeudi 31 mars 2016 à 11h00, IPAG seminar room

High resolution X-ray spectra of black hole X-ray binaries (BHBs) show blueshifted absorption lines from disk winds which seem to be equatorial. Winds occur in the Softer (disk-dominated) states of the outburst and are less prominent or absent in the Harder (power-law dominated) states. We use self-similar magneto-hydrodynamic (MHD) accretion-ejection models to explain the disk winds in BHBs. In our models, the density at the base of the outflow from the accretion disk is not a free (…)

Séminaire

Séminaire IPAG de Didier Fraix-Burnet (IPAG), jeudi 7 avril 2016 à 11h00, IPAG seminar room

I would like to present the status of astrocladistics, a new branch of research that consists in the use of phylogenetic tools for classification in astrophysics, that I started in 2001. Exactly fifteen years later, a few facts lead me to consider this heavy, risky, original and exciting investment as a success. In this talk, I will make a review of the achievements insisting on the many astrophysical results and projects regarding stellar populations, globular clusters, galaxies and gamma (…)

Séminaire

Séminaire IPAG de Bernard Schmitt (IPAG), jeudi 28 avril 2016 à 11h00, IPAG seminar room

Since the flyby of Pluto and its five moons on 14 July 2015 part of the 50Go of measurements recorded by its 5 instruments have been downloaded to Earth and calibrated. A number of interesting discoveries have been made in various fields on Pluto, Charon and the 4 small satellites. Pluto’s surface was found to display a wide variety of landforms and terrain ages, as well as dramatic albedo, color, and compositional variegation. In particular some of its geologically young surface units are (…)

Séminaire

Séminaire IPAG de Mathieu Bathelemy (IPAG), jeudi 12 mai 2016 à 11h00, IRAM seminar room

The Grenoble University Space Center aims to involve students in nanosatellites building and development. We work with students from different levels and different domains including some human science formation. It is however not only a training center. Nanosatellites are changing the paradigm of space exploration and engineering. The past 15 years have seen a growing activity in this field, with a marked acceleration in the last 3 years. Whereas the educational value of nanosatellites is (…)

Séminaire

Séminaire IPAG de Eric Lagadec (Lagrange), jeudi 19 mai 2016 à 11h00, IRAM seminar room

SPHERE is an extreme adaptive optics instruments mounted on the Very Large Telescope in Chile, designed for the direct detection of planet and the study of discs around young stars.
I will show you that SPHERE can be used to tackle a large variety of questions, from the solar system to extragalactic studies. My main focus will be on the mass loss from evolved stars, as SPHERE is currently revolutionizing the way we understand this crucial phase for stellar and galactic evolution. For the (…)

Séminaire

Séminaire IPAG de David Maurin (LPSC), jeudi 26 mai 2016 à 11h00, IRAM seminar room

The annihilation of dark matter particles into gamma-rays is one of the most promising channels for indirect detection. The ideal targets are regions of high dark matter density, close, and free of astrophysical background. In this context, after briefly reviewing the various interesting targets, I will focus more specifically on the dwarf spheroidal galaxies. I will discuss the determination of their dark matter profile and the related uncertainties, and how this affects their ranking as (…)

Séminaire

Séminaire IPAG de Luc Dessart (Lagrange), jeudi 9 juin 2016 à 11h00, IRAM seminar room

In recent years, stellar explosions (or more generally supernovae, SNe), have become the focus of considerable interest in modern astrophysics. These short-lived phenomena reach extraordinary peak luminosities of 10^7 to 10^11 Lsun, making them excellent probes of the distant Universe. They represent the ultimate demise of different types of stars. The so-called SNe Ia, in part associated with the explosion of accreting white dwarfs at the Chandrasekhar mass, lead to the combustion, on a (…)

Séminaire

Séminaire IPAG de Nicolas Fray (LISA), jeudi 16 juin 2016 à 11h00, IRAM seminar room

COSIMA - COmetary Secondary Ion Mass Analyser – is an instrument dedicated to the study of cometary particles on board the Rosetta orbiter. Since August 2014, COSIMA is capturing cometary dust particles in the inner coma of the comet 67P/Churyumov-Gerasimenko onto metal target plates. COSIMA images and identifies the particles with an optical microscope with a resolution of 14 um per pixel and analyses their composition with a time of flight secondary ion mass spectrometer with a mass (…)

Séminaire

Séminaire IPAG de Ralph Pudritz (Mc Master University, MPIA), lundi 4 juillet 2016 à 11h00, IPAG seminar room

With over three thousand confirmed exoplanets known, distinct planetary populations that bear little resemblance to the Solar System can now be discerned. Among these are Hot Jupiters orbiting at the relative orbit of Mercury, warm and more massive Jupiters at 1 AU, and the dominant population of SuperEarths and mini Neptunes with their close-in orbits. How are planetary properties, in particular their chemical composition and that of their atmospheres, connected to their formation in (…)