The fates of massive stars: exploring uncertainties in stellar evolution with METISSE

TL;DR

This paper introduces METISSE, a flexible interpolation-based method for stellar evolution modeling that improves accuracy and speed over traditional SSE, enabling better understanding of massive star evolution and its uncertainties.

Contribution

METISSE provides a more adaptable and faster alternative to SSE by interpolating between detailed stellar tracks, enhancing the study of stellar evolution uncertainties.

Findings

METISSE better reproduces detailed stellar tracks than SSE.

Remnant mass predictions vary by up to 20 M$_\odot$ across models.

Maximum radial expansion can differ by an order of magnitude.

Abstract

In the era of advanced electromagnetic and gravitational wave detectors, it has become increasingly important to effectively combine and study the impact of stellar evolution on binaries and dynamical systems of stars. Systematic studies dedicated to exploring uncertain parameters in stellar evolution are required to account for the recent observations of the stellar populations. We present a new approach to the commonly used Single-Star Evolution (SSE) fitting formulae, one that is more adaptable: Method of Interpolation for Single Star Evolution (METISSE). It makes use of interpolation between sets of pre-computed stellar tracks to approximate evolution parameters for a population of stars. We have used METISSE with detailed stellar tracks computed by the Modules for Experiments in Stellar Astrophysics (MESA), Bonn Evolutionary Code (BEC) and Cambridge STARS code. METISSE better reproduces stellar tracks computed using the STARS code compared to SSE, and is on average three times faster. Using stellar tracks computed with MESA and BEC, we apply METISSE to explore the differences in the remnant masses, the maximum radial expansion, and the main-sequence lifetime of massive stars. We find that different physical ingredients used in the evolution of stars, such as the treatment of radiation dominated envelopes, can impact their evolutionary outcome. For stars in the mass range 9 to 100 M$_\odot$, the predictions of remnant masses can vary by up to 20 M$_\odot$, while the maximum radial expansion achieved by a star can differ by an order of magnitude between different stellar models.