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About me

I am a PhD candidate in astronomy and astrophysics at LESIA, Paris Observatory, and at the Subaru Telescope in Hawaii, working with Anthony Boccaletti and Olivier Guyon. I am a visiting PhD candidate at UCL, under the mentorship of Giovanna Tinetti.

My main research interests are in exoplanets, those planets rotating around other stars than our Sun. Especially, I work in high contrast imaging, understanding the formation processes of exoplanets by studying disks. Furthermore, I am interested in the atmospheric characterisation of exoplanets detected via transit.

I am originally from Robion, a village in Provence, south of France, where I developed my passion for astronomy in high school. I moved to Paris to pursue my undergraduate studies in fundamental physics at Jussieu, Sorbonne University, I then joined an engineering school in optics and photonics, the Institut d’Optique Graduate School, as I wanted to acquire skills in astronomical instrumentation. I finished my masters with a dual international degree with Imperial College London, with an MSc in Physics, with astrophysics-related courses.

Besides my passion for astronomy, exoplanets, and especially the search for life in the universe, I have photography as a hobby: mainly night sky pictures. I deeply enjoy outdoor activities: hikes and ocean sports, I free dive, scuba dive, and surf.

Outreach

I regularly give public talks to share my passion for astronomy.

I started outreach in the astronomy center of Saint-Michel-l’Observatoire, where I worked for two consecutive summers in 2012 and 2013 as astronomy mediator.

Selection of recent outreach talks:

  • Why explore space? (in French) - April 2021 - Association Jeunes IHEDN.
  • Initiation to astronomie (in French) - December 2019 - Culturel center of Villeneuve d’Ascque.
  • Introduction to astronomy - August 2019, FEC Scouts, London.
  • Initiation to astronomy in Hawaii (in French) - April 2018, Rotary Club of Cavaillon.

I participate punctually with associations, such as AniMath, which is focused on communication with high school girls.

Photography

Night sky photography is a hobby that I started in 2017, when I first discovered the speechless beauty of a sky free of light pollution in Hawaii.

I have a Sony Alpha 7 III, and a Sony Alpha 7. My lenses are a Samyang 14mm f/2.8, and a Sony 24-70mm f/2.8. I often post some of my pictures on my Flickr account. Feel free to contact me for prints!

Some of my pictures have been featured on the TV show Everything Hawaii by Kawika.

Teaching

Tutoring

I have an extensive experience as a private tutor, from middle school to undergraduate level, in mathematics, physics and chemistry.

I have worked for a couple of years with the company “Scolaridée”, which whom I worked to prepare students for the entering competition of engineering schools.

Invited lectures

I have given some lectures as invited lecturer :

  • Direct imaging of exoplanets - Invited lecturer in Giovanna Tinetti's exoplanet course at UCL, UK, February 2021. Masters level.
  • Exoplanets and Ocean Worlds - Invited lecturer in Karen Gallardo’s oceanography course in a community college in California, USA, February 2021. Undergraduate Level.

Research

The discovery of the first exoplanet almost 25 years ago revolutionized the world of astronomy. Since then, nearly 5,000 planets have been detected, presenting an incredible diversity and questioning our understanding of planetary formation. The number of temperate rocky planets in our galaxy is estimated to be 60 billion. The systems discovered are so different from the solar system that one wonders if the latter is a special case. Questions then arise: how different are these planets? What are the processes leading to their formation? Or, what is our place in the universe? Are there other forms of life? Answering these questions is complex and requires a detailed study of the population of exoplanets. But imaging exoplanets and acquiring spectra of their atmospheres is particularly demanding. Indeed, for a photon received from a temperate rocky planet, there are more than 109 photons coming from the host star (which defines the contrast). For more than a decade, technological developments have been such that we now know how to operate instruments with very high contrasts, made up of sophisticated coronagraphs, which is comparable to an artificial eclipse, and of an Adaptive Optics system (AO), which partially compensates for the influence of the Earth's atmosphere and improves image quality.

My intimate ambition aligns with this quest for instrumental and scientific perfection for the direct imaging of exoplanets. My thesis is made of two major axes: the development of instrumental tools to improve the imaging quality of the AO system; and the analysis of astrophysical data from planetary systems.

Adaptive Optics Beta Pictoris Atmospheric characterisation of exoplanets Exoplanet detection with deep learning

Adaptive Optics

So far, astronomers have used a dedicated wave surface analyzer to measure the aberrations induced on the star's light: the AO corrects the aberrations measured by the analyzer, ideally approaching a state free of aberrations. But the focal point of the AO, defined by the analyzer, does not correspond perfectly to an optimal image quality.

In order to correct these aberrations, I developed the DrWHO (Direct Reinforcement Wavefront Heuristic Optimization) algorithm. The method is such that, from scientific images, image quality is constantly optimized by the adaptive optics. For the first time, an AO system is now able to learn how to self-optimize by considering the scientific focal plane image. After validating DrWHO in simulation, I applied it on sky in December 2020, on the SCExAO instrument at the Subaru telescope in Hawaii, which is one of the largest non-segmented telescopes. Figure 2 shows the comparison without and with DrWHO compensation after only 10 minutes of run: the image obtained with DrWHO is notably improved, approaching an Airy spot. This image, thanks to DrWHO, is one of the best images in the world ever acquired with such quality in the visible with such a telescope, if not the best. This is a star image. I am now working on sky optimization DrWHO for a planetary system.

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Beta Pictoris

Beta Pictoris is a fascinating young system, composed of a circumstellar disk, at least two Jovian exoplanets, exocomets, and exhibits complex dynamics. This system has been intensively observed since its discovery in 1984, giving us constraints on the conditions of planetary formation. I analyzed the first high contrast mid-infrared observations taken with the VLT. I concluded with an upper limit of contrast of the planet at 10 microns, allowing to constrain atmospheric scenarios. In addition, the disk exhibits two structures of dust clusters, one of which had never been previously observed. I am currently analyzing these two clusters to understand their origin.

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Atmospheric characterisation of exoplanets

Spectral analysis of the atmospheres of exoplanets is fundamental to understanding their composition, their formation, and possibly detecting traces of biosignatures. I developed my expertise in this area by analyzing the atmospheres of three “hot jupiters”, WASP-127b, WASP-79b and WASP-62b . Hot jupiters are particularly mysterious for their large sizes, short period, and intense temperatures. All three planets present water features in their atmosphere. All three may present iron hydrate (FeH) abundances, however further observations are required to confirm it.

Spectrum of WASP-127b, with its retrieval.

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