The formation and properties of exoplanetary systems is a fascinating question, which has been at the heart of our quest to define mankind and the conditions for life to develop in a broader context. Observations suggest there should be billions of planets in our Galaxy alone. What are the physical process that make planet formation so likely ? Which local conditions are required to transform the stardust of the interstellar medium into pebbles around young stars, and grow these further into planets ? Investigating the dust evolution along the star formation sequence is key to provide a complete picture of the planet formation scenario.
Moreover, the dust grains are crucial because they regulate some key physical processes: for example, the amount of small grains is a key parameter to set the coupling of magnetic fields, hence regulating the sizes and masses of the protostellar disks when they are assembled.

Recently, the star formation group at CEA has obtained some of the first observational clues that the dust particles contained in the pristine disk-forming reservoirs that are the embedded protostars may already have significantly evolved from the submicronic dust populating the interstellar medium.
The proposed PhD aims at exploring new dataset, observations of young protostars from the infrared to the millimeter wavelengths and investigate wether dust particles are indeed growing significantly already during the first 0.5 Myrs of the star formation process.
To improve our understanding of early dust evolution during the disk-building phase, this analysis of multi-scale observational data will be compared to the predictions of evolved dust models implemented in MHD numerical simulations of disk formation.

The student will analyze data obtained with the NIRSpec/NIRCam, then MIRI, instruments aboard the James webb Space Telescope, towards nearby embedded protostars. This data should probe the presence of micronic dust grains in the close vicinity of the young forming disks. The analysis of complementary dust emission maps from the ALMA and NOEMA interferometers, probing the colder dust, will complete the picture, allowing a multi-wavelength approach to constrain the models.