MODULES FOR EXPERIMENTS IN STELLAR ASTROPHYSICS (MESA)

TLDR

MESA is an open‑source, robust, efficient, thread‑safe library suite that supports a wide range of computational stellar‑astrophysics research. MESAstar, the one‑dimensional stellar‑evolution module, integrates numerous physics and numerical components—solving fully coupled structure and composition equations with adaptive mesh refinement, sophisticated timestep controls, and OpenMP parallelism—while each Fortran‑95 module exposes a clear public interface for independent development. Extensive verification through detailed examples demonstrates MESA’s capabilities across the full spectrum of stellar evolution, from very low‑mass stars and brown dwarfs to massive stars, including solar sound‑speed profiles, pulsating B stars, thermal pulses on the asymptotic giant branch, and mass transfer or helium accretion onto compact objects. MESA can be downloaded from the project website (http://mesa.sourceforge.net/).

Abstract

Stellar physics and evolution calculations enable a broad range of research in astrophysics. Modules for Experiments in Stellar Astrophysics (MESA) is a suite of open source, robust, efficient, thread-safe libraries for a wide range of applications in computational stellar astrophysics. A one-dimensional stellar evolution module, MESAstar, combines many of the numerical and physics modules for simulations of a wide range of stellar evolution scenarios ranging from very low mass to massive stars, including advanced evolutionary phases. MESAstar solves the fully coupled structure and composition equations simultaneously. It uses adaptive mesh refinement and sophisticated timestep controls, and supports shared memory parallelism based on OpenMP. State-of-the-art modules provide equation of state, opacity, nuclear reaction rates, element diffusion data, and atmosphere boundary conditions. Each module is constructed as a separate Fortran 95 library with its own explicitly defined public interface to facilitate independent development. Several detailed examples indicate the extensive verification and testing that is continuously performed and demonstrate the wide range of capabilities that MESA possesses. These examples include evolutionary tracks of very low mass stars, brown dwarfs, and gas giant planets to very old ages; the complete evolutionary track of a 1 M☉ star from the pre-main sequence (PMS) to a cooling white dwarf; the solar sound speed profile; the evolution of intermediate-mass stars through the He-core burning phase and thermal pulses on the He-shell burning asymptotic giant branch phase; the interior structure of slowly pulsating B Stars and Beta Cepheids; the complete evolutionary tracks of massive stars from the PMS to the onset of core collapse; mass transfer from stars undergoing Roche lobe overflow; and the evolution of helium accretion onto a neutron star. MESA can be downloaded from the project Web site (http://mesa.sourceforge.net/).