MODULES FOR EXPERIMENTS IN STELLAR ASTROPHYSICS (MESA): PLANETS, OSCILLATIONS, ROTATION, AND MASSIVE STARS

Abstract

We substantially update the capabilities of the open source software package\nModules for Experiments in Stellar Astrophysics (MESA), and its one-dimensional\nstellar evolution module, MESA Star. Improvements in MESA Star's ability to\nmodel the evolution of giant planets now extends its applicability down to\nmasses as low as one-tenth that of Jupiter. The dramatic improvement in\nasteroseismology enabled by the space-based Kepler and CoRoT missions motivates\nour full coupling of the ADIPLS adiabatic pulsation code with MESA Star. This\nalso motivates a numerical recasting of the Ledoux criterion that is more\neasily implemented when many nuclei are present at non-negligible abundances.\nThis impacts the way in which MESA Star calculates semi-convective and\nthermohaline mixing. We exhibit the evolution of 3-8 Msun stars through the end\nof core He burning, the onset of He thermal pulses, and arrival on the white\ndwarf cooling sequence. We implement diffusion of angular momentum and chemical\nabundances that enable calculations of rotating-star models, which we compare\nthoroughly with earlier work. We introduce a new treatment of\nradiation-dominated envelopes that allows the uninterrupted evolution of\nmassive stars to core collapse. This enables the generation of new sets of\nsupernovae, long gamma-ray burst, and pair-instability progenitor models. We\nsubstantially modify the way in which MESA Star solves the fully coupled\nstellar structure and composition equations, and we show how this has improved\nMESA's performance scaling on multi-core processors. Updates to the modules for\nequation of state, opacity, nuclear reaction rates, and atmospheric boundary\nconditions are also provided. We describe the MESA Software Development Kit\n(SDK) that packages all the required components needed to form a unified and\nmaintained build environment for MESA. [Abridged]\n