Stellar-MADE project
Antoine Alaguero
Education
At present, I am pursuing a PhD as part of the Stellar-MADE project at IPAG/CNRS (France). I have a Bachelor’s degree in Physics and recently completed a Master’s degree in Astrophysics, both of which I obtained in Grenoble (France). My first experience in research was a Master’s internship during summer 2021. It was supervised by Nicolás Cuello and was focused on the dynamics of protoplanetary discs in triple systems. I performed hydrodynamical simulations of the young triple system V892 Tau. The goal was to establish a connection between the disc and the orbit of the outer star of the system. The following year, I did another Master’s internship with Myriam Benisty and François Ménard in the planet formation field. The objective was to assess the potential of the upcoming Extremely Large Telescope regarding young stellar systems. My task was to estimate the detectability of young planets embedded in their host disc and the detectability of the disc itself. I am continuing this work in the context of the ELT/MORFEO JeDiEx working group.
PhD project - Planet formation in multiple stellar systems
Protoplanetary discs set the initial conditions for planet formation, as the dust particles they contain eventually grow into planets. This process fully depends on the dust dynamics, which are determined by the interactions with both gas and larger bodies of the system. Understanding dusty disc dynamics is then a key step to understand how planets form. In multiple stellar systems, several kinematic effects are expected to modify the disc(s) dynamics, producing substructures inside the disc(s). My first goal is to characterize discs in typical multiple systems both observationnally and numerically to assess their dynamical response to multiplicity. Comparing actual observations to numerical simulations (Hydrodynamical+Radiative Transfer), I aim to understand to what extent multiplicity shape disk morphology and dynamics in young stellar systems.
Once the dust dynamics properly understood, the second step is to understand to what extent these dynamics impact the dust growth. In order to do so, I will use a combination of hydrodynamical simulations and dust growth algorithm, processed with a radiative transfer code. In this way, I will highlight the regions where dust particles either fragmentate or agglomerate, and thus the favored regions for planets to form in multiple systems.
Ongoing work
Dust growth in binary systems
Stars often form in multiple systems, where star-disc interactions influence protoplanetary disc dynamics and dust growth. In these systems, high dust velocity dispersion from gravitational effects of nearby companions can impede dust particle growth, yet the formation of substructures like spiral arms can enhance collision rates and growth potential due to increased density. Therefore, the impact of multiplicity on planet formation remains uncertain. To investigate this question, I perform 3D hydrodynamical simulations of binary systems in various orbital configurations with circumstellar and circumbinary discs. The simulations are integrated with dust growth and fragmentation over a total time of at least 100 000 years, which allows to derive robust results. The analysis focuses on dust spatial and size distributions to evaluate the planet-forming potential in binary systems.
ELT observations
In the context of the forthcoming giant telescopes, accessible probed resolutions will soon be greatly upgraded, unveiling the very inner separations of stellar systems. My task is to assess how much this will improve the capability to detect exoplanets and characterize disk substructures in young stellar systems. This task is part of the science cases of the ELT/MICADO and ELT/HARMONI instruments. To adress this question, I am performing full radiative transfer simulations of a typical young stellar system using the radiative transfer code MCFOST. I then transform those simulations into synthetic observations of the ELT instruments. By analyzing these observations, I derive detection limits for embedded planets depending on the initial system configuration.
Recent Highlights
Modelling of triple stellar systems (V892 Tau)
V892 Tau is a young triple stellar system with a CircumBinary Disc (CBD). The orbit of the inner binary is well known and the CBD is well characterized, but the orbit of the outer companion V892 Tau NE remains unconstrained. As seen on new ALMA high-resolution observations, the CBD is highly structured and the presence of such substructures could be due to interactions with the outer star. Using hydrodynamical simulations post-processed into synthetic observations, I showed that an eccentric misaligned orbit of the companion can account for the observed substructures in the CBD, demonstrating the ongoing interactions with V892 Tau NE.