My research focuses on better understanding planetary system architectures, using an observational perspective.

My main questions of interests:

  • What is the diversity of planetary system architectures? What does it tell us about planet formation and evolution? How can we relate it to the origin of our Solar System?

  • How do the morphologies of debris disks constrain the underlying planet population?

On November 14, I will start as a Fellow at the European Southern Observatory in Chile, with observational duties on the Very Large Telescope (VLT) in the Atacama desert.

Previously, I carried out my Ph.D. at the University Grenoble Alpes in France, half-time at the Institut de Planétologie et d’Astrophysiques de Grenoble, and half-time at the Max Planck Institute for Astronomy in Heidelberg, Germany. My Ph.D. aimed to better understand planet formation by peering into the architecture of planetary systems. In practice, I characterized known exoplanets (orbital motion, spectral emission), and looked for additional exoplanets. In addition, I am interested in debris disks, characterizing their emission and morphology. During my Ph.D., I used different astronomical facilities, and in particular the VLT/SPHERE instrument in Chile. I am part of the SPHERE and SPHERE+ consortia. In the SPHERE+ consortium, I worked in the astro simulations group, in particular on the design of the medium resolution spectrograph. Therefore, my Ph.D. wass strongly based on both observational and instrumental aspects.

After seven years of operations, SPHERE is one of the most efficient disks and exoplanet imagers worldwide. As the signal extraction and data processing of faint exoplanets or disks from observations requires a deep understanding of the instrument, it is highly valuable to combine instrumental studies and astrophysical interpretation.

From an observation perspective, my main objects of interest are young and nearby systems. From a few millions years old as the protoplanetary disks which are the birth places where exoplanets form, to about twenty million year old when the gas in the system has vanished but the putative exoplanets or debris disks emit still enough light in the near infrared to be observed. At a few giga year old, direct-imaging observations have poor sensitivity and can detect only companions close to the regime of brown dwarves to date. Yet, observing old systems can be mandatory if one wants to combine direct-imaging observations with radial velocity measurements sensitive to small planets, as super-Earths. Old stars are more stable, increasing a lot the sensitivity of radial velocity measurements. That’s why in one of my Ph.D. projects, I target stars between 500 Myr and 10 Gyr.


[HD 95086 (young system at 86 pc)  versus  GJ 229 (old system at 6 pc)]


How did I start to work in the field of direct imaging of exoplanets?

I have started to work in this field, and in particular with the instrument SPHERE, thanks to my research internships in my Master studies, the first one dating back to 2019.

An observer in astrophysics wears several hats: from writing the proposal and making the observation blocks, to the data acquisition, processing and analysis. I enjoy experiencing these different jobs. In particular,

  • In 2019, I had the chance to go at Paranal to observe with VLT/SPHERE in visitor mode. Since 2020, I submitted proposals with various facities: ESO, LBT, JWST, HST, and got granted part of them (see my Resume).
  • During a master internship at the Max-Planck Institute for Astronomy in Germany, I investigated baseline to cutting-edge image processing techniques. The goal was to retrieve directly-imaged protoplanetary disks in near infrared to look for proto-exoplanets creating the observed substructures inside the disks. This project was carried out in the context of the paper from Assenssio-Torres et al. 2021.


    • PDS 70 processed with the Mayo pipeline described in Pairet et al. 2020.

  • I led an in-depth direct-imaging and spectroscopic characterization on the young exoplanetary system HD 95086, recently published (Desgrange et al. 2022).
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    Overview of the HD 95086 system. This is a composite image with in pink the outer belt resolved by ALMA (Su et al. 2017) and in yellow the exoplanet b seen by VLT/SPHERE (Chauvin et al. 2018).
    Figure from Desgrange et al. 2022.

    After acquiring, processing and analyzing observation, I chose to experience the other side of the mirror: instrumentation. During my master's thesis, I looked into instrumental limitations from polarization effects known as the Goos-Hänchen and Imbert-Fedorov effects. I compared theoretical predictions to experiments on the optical high-contrast imaging testbed Très Haute Dynamique 2 (THD 2) bench at the Observatoire de Paris.


    Polarization effects on the THD 2 bench



    (work in progress)