The study of stellar oscillations has allowed significant progress in the modelling of low-mass stars over the last few decades but has left out intermediate- and high-mass stars (above 1.5 solar masses). These stars are of utmost importance as they drive the chemical enrichment of the Galaxy and are the progenitors of supernovae, neutron stars and black holes.
To extend asteroseismology’s probing power towards higher masses, the best candidates are the abundant delta Scuti pulsators. However, the rapid rotation they harbour (>100 km/s at the equator) makes the interpretation of observations and the modelling of these stars difficult and requires dedicated 1D and 2D stellar models and oscillation calculations. It is unclear whether this rotation can emerge from formation processes or binary interactions, while the inner rotation of stars is also more homogeneous than expected. Understanding the origin and redistribution of angular momentum is the final goal of the EREBOS project. The main steps include defining a set of benchmark stars, that associate asteroseismic, spectroscopic, binary orbit and/or interferometric measurements to test the various state-of-the-art modelling tools available. Assessing the various codes' respective limitations, using the most relevant ones derive the most accurate parameters for rapid rotators to date, and building extensive grids of models are the key steps of the project.
This will pave the way to ensemble asteroseismology of intermediate-mass pulsators, and open a window on the evolution of rotation rates and the internal angular momentum redistribution across the stellar lifetimes.
EREBOS is a project funded by the Junta de Andalucía through their talent attraction program Emergía, grant EMEC_2023_00533.