2 sujets /DAp/LDE3

Dernière mise à jour : 14-08-2020


 

Tidal dissipation in giant planets: new generation ab-initio models at the time of space missions

SL-DRF-20-0501

Research field : Astrophysics
Location :

Direction d’Astrophysique (DAP)

Laboratoire de dynamique des étoiles des (Exo) planètes et de leur environnement (LDE3)

Saclay

Contact :

Stéphane MATHIS

Starting date : 01-10-2020

Contact :

Stéphane MATHIS
CEA - DRF/IRFU/DAP/LDE3

0169084930

Thesis supervisor :

Stéphane MATHIS
CEA - DRF/IRFU/DAP/LDE3

0169084930

Laboratory link : http://irfu.cea.fr/dap/LDEE/index.php

Gaseous giant planets like Jupiter and Saturn in our solar system and “hot” Jupiters orbiting around other stars with very short periods are complex and fascinating objects. Indeed, they are turbulent rotating magnetic bodies that have strong interactions with their environment: their moons in the case of Jupiter and Saturn and their host stars in the case of “hot” Jupiters/Saturns. In such gaseous giant planets’ systems, tidal forces, the tidal waves they excite and their dissipation shape the orbital architecture and the rotational dynamics of the planets. During the last decade, several revolutions have occurred for our understanding of tides in these systems. On the one hand, high precision astrometry and the CASSINI (NASA/ESA) space mission have measured dissipation stronger by one order of magnitude than expected in Jupiter and Saturn. On the other hand, the large space-based photometric surveys Kepler/K2 and now TESS (NASA) are observing a broad diversity of orbital architecture for exoplanetary systems while “hot” gaseous giant planets seems to host a weakest tidal dissipation than Jupiter and Saturn. Finally, the space mission JUNO (NASA) and the grand finale of CASSINI have revealed the internal structure and dynamics of Jupiter and Saturn: the intense zonal flows observed at their surface are confined in their external layers because of the action of the magnetic field in their deepest regions while the heavy elements contained in their core are mixed in their deep gaseous envelope that modifies the global structure of the planet. The objective of this PhD project is thus to build the new coherent models of tidal dissipation in gaseous giant (exo-)planets mandatory to understand the evolution of their systems. They will take into account all these complex phenomena and new observational constraints. These models will be applied to predict the evolution of planetary systems in support of ongoing and forthcoming space missions in which the CEA-IRFU Department of Astrophysics is strongly involved (JWST, PLATO, ARIEL).
Exoplanet atmospheres with the JWST and ARIEL space missions : fighting against instrumental systematics upstream with ARIEL and downstream with JWST

SL-DRF-20-0506

Research field : Astrophysics
Location :

Direction d’Astrophysique (DAP)

Laboratoire de dynamique des étoiles des (Exo) planètes et de leur environnement (LDE3)

Saclay

Contact :

Pierre-Olivier LAGAGE

Starting date : 01-10-2020

Contact :

Pierre-Olivier LAGAGE
CEA - DRF/IRFU/DAP/LDE3

+33676738723

Thesis supervisor :

Pierre-Olivier LAGAGE
CEA - DRF/IRFU/DAP/LDE3

+33676738723

The study of exoplanets is booming. Since the detection of the 1st exoplanet in 1995 by Mr. Mayor and D. Queloz (2019 Nobel Prize in Physics), more than 4000 exoplanets have been detected. The domain is now faced with a new challenge: the characterisation of the atmosphere of exoplanets. Knowledge of the atmosphere brings unique information to constrain the formation and evolution of the exoplanet, its interior, even the presence of biological activity, etc. This characterisation will take a considerable step forward with the launch of two space missions: the JWST in 2021 and the ARIEL mission, entirely dedicated to exoplanet atmospheres, in 2028. The atmosphere is studied from spectroscopic infrared observations; the level of instrumental stability required for these studies is very high (up to 10 ppm over 10 hours).

The JWST was not designed to have the required stability. During his/her thesis the student will determine the stability in flight of the JWST MIRI instrument, to which CEA has made a strong contribution, will compare it with the predicted one and will analyse different methods to improve the stability during data reduction. CEA is also strongly involved in the ARIEL mission (mastery of the main instrument of ARIEL: the AIRS infrared spectrometer; realization and testing of the detection chain). The student will participate in the studies of the instrumental stability (laboratory tests of the detection chain, analysis of results, determination of the best operating modes, system analysis) in order to maximize the instrumental stability upstream to the launch.

Key words : space missions, infrared detectors, exoplanets

 

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