A New, Efficient Stellar Evolution Code for Calculating Complete Evolutionary Tracks

TL;DR

This paper introduces a new, efficient stellar evolution code capable of calculating complete evolutionary tracks across various masses and metallicities, suitable for modeling dense stellar systems and merger-products with high accuracy.

Contribution

The paper presents a novel, fully implicit, adaptive-grid stellar evolution code that can follow all evolutionary phases without interruption, improving modeling speed and accuracy.

Findings

Achieves better than 1% accuracy in solar models

Successfully models stars from pre-main-sequence to white dwarf or core collapse

Derives an initial-final mass relationship consistent with previous studies

Abstract

We present a new stellar evolution code and a set of results, demonstrating its capability at calculating full evolutionary tracks for a wide range of masses and metallicities. The code is fast and efficient, and is capable of following through all evolutionary phases, without interruption or human intervention. It is meant to be used also in the context of modeling the evolution of dense stellar systems, for performing live calculations for both normal star models and merger-products. The code is based on a fully implicit, adaptive-grid numerical scheme that solves simultaneously for structure, mesh and chemical composition. Full details are given for the treatment of convection, equation of state, opacity, nuclear reactions and mass loss. Results of evolutionary calculations are shown for a solar model that matches the characteristics of the present sun to an accuracy of better than 1%; a 1 Msun model for a wide range of metallicities; a series of models of stellar populations I and II, for the mass range 0.25 to 64 Msun, followed from pre-main-sequence to a cool white dwarf or core collapse. An initial final-mass relationship is derived and compared with previous studies. Finally, we briefly address the evolution of non-canonical configurations, merger-products of low-mass main-sequence parents.