Scaled solar tracks and isochrones in a large region of the Z-Y plane. II. From 2.5 to 20 solar masses

TL;DR

This paper extends stellar evolutionary models to intermediate and massive stars across a broad range of chemical compositions, providing new tools and data for astrophysical research on star evolution and populations.

Contribution

It introduces a comprehensive grid of evolutionary tracks and isochrones for 2.5 to 20 solar masses with varied chemical compositions, including software tools for interpolation and population simulation.

Findings

Tracks and isochrones match observed red supergiants.

Blue loop extensions and Cepheid instability strips analyzed.

Software tools enable customized stellar population modeling.

Abstract

We extend our theoretical computations for low-mass stars to intermediate-mass and massive stars, for which few databases exist in the literature. Evolutionary tracks and isochrones are computed from 2.50 to 20 solar masses for agrid of 37 chemical compositions with metal content Z between 0.0001 and 0.070 and helium content Y between 0.23 and 0.40. Synthetic TP-AGB models allow stellar tracks and isochrones to be extended until the end of the thermal pulses along the AGB. We provide software tools for the bidimensional interpolation (in Y and Z) of the isochrones. We present tracks for scaled-solar abundances and the corresponding isochrones from very old ages down to about 10 million years. The extension of the blue loops and the instability strip of Cepheid stars are compared and the Cepheid mass-discrepancy is discussed. The location of red supergiants in the H-R diagram is in good agreement with the evolutionary tracks for masses from 10 to 20 solar masses. Tracks and isochrones are available in tabular form for the adopted grid of chemical compositions in the extended plane Z-Y in three photometric systems. An interactive web interface allows users to obtain isochrones of any chemical composition inside the provided Z-Y range and also to simulate stellar populations with different Y(Z) helium-to-metal enrichment laws.