École Nationale Supérieure de
Techniques Avancées

Résumé

This internship report focuses on improving stellar models through the development of new opacity and radiative acceleration tables. These efforts are crucial for the upcoming PLATO mission, scheduled for 2026, which aims to discover and characterize new exoplanets by observing the brightness variations of stars. The primary challenge lies in enhancing stellar opacity models, particularly for chemical elements such as carbon (C), nitrogen (N), and oxygen (O), whose abundances have recently been revised downward, leading to discrepancies between standard solar models and observations. During this internship, new opacity and radiative acceleration tables were developed using data from the Opacity Project (OP), with the integration of additional parameters. These tables were then incorporated into the stellar code YREC7 to assess their impact on stellar modeling. The report includes a literature review on stellar opacities, a detailed description of the methodology used, and an analysis of the results obtained, along with their implications for improving stellar models.