Lundi 1er février 2021 à 16h00 (En visioconférence)
Lucia Mandon (LESIA)
The exploration of Mars will soon be marked by a historic turning point, with the in situ investigation of two sites of Noachian age, the most primitive era of Mars. The selected landing sites, Jezero crater (Mars 2020 mission, NASA) and Oxia Planum (ExoMars mission, ESA/Roscosmos), exhibit from orbital data evidences for a hydrous past as well as good astrobiological potentials.
This talk will focus on the lessons learned from the geology of these sites and what constrains it can provide on the early history of Mars. In particular, we will present one of the most extensive geological units on the Mars 2020 landing site, the olivine and carbonate unit. We suggest a pyroclastic origin for these deposits and date their emplacement. This age will be useful to help calibrate the Martian chronology in the events of the Mars Sample Return mission. While the ExoMars landing site appears spectrally homogeneous from orbit, we show that there is textural, compositional, and mineralogical diversity at high resolution within the clays present at the site, which are the primary targets of the mission.
Jeudi 28 janvier 2021 à 16h00 (En visioconférence)
Benoît Neichel (LAM)
In few years from today, the largest optical telescope ever built will start exploring the Universe. This giant of 39m diameter - the European Extremely Large Telescope (ELT) - will address fundamental astrophysical science cases as for instance the direct imaging and characterization of exo-worlds or the study of bulk and evolution of the first galaxies. To fully exploit the scientific potential of the ELT, it will be equipped with a suit of instruments, amongst which HARMONI is the first light Integral Field Spectrograph.
HARMONI will observe in the visible and near infra-red range (from .5 to 2.4 microns), with a spectral resolution covering from R = 3000 to R = 20000, and at an angular resolution from 60mas and down to 4mas. HARMONI has been designed to exploit the diffraction limit of the ELT, and it will be equipped with two Adaptive Optics (OA) systems. The first is a conventional OA system (SCAO) and the second will be a high sky-coverage AO system, assisted by laser (LTAO).
In this presentation, we will first see the specificities of the future ELT, and in particular the technological challenge it represents to provide an optimal image quality. I will then focus on HARMONI, providing a description of the instrument and the current status of the project. Finally, I will illustrate some scientific cases unique to the ELT, and in particular to the HARMONI instrument.
Pour assister au séminaire, contacter johan.mazoyer obspm.fr
Jeudi 21 janvier 2021 à 14h00 (En visioconférence)
Mathieu Puech et Myriam Rodrigues (GEPI)
MOSAIC is the planned multi-object spectrograph for the 39m Extremely Large Telescope (ELT). Conceived as a multi-purpose instrument, it others both high multiplex and multi-IFU capabilities at a range of intermediate to high spectral resolving powers in the visible and the near-infrared. MOSAIC will enable unique spectroscopic surveys of the faintest sources, from the oldest stars in the Galaxy and beyond to the first populations of galaxies that completed the reionisation of the Universe while simultaneously opening up a wide discovery space. I will present the status of the instrument ahead of Phase B, showcasing the key science cases as well as introducing the updated set of top level requirements and the adopted architecture. The high readiness level will allow MOSAIC to soon enter the construction phase, with the goal to provide the ELT community with a world-class MOS capability as soon as possible after the telescope first light.
