The Effects of Stellar Rotation. I. Impact on the Ionizing Spectra and Integrated Properties of Stellar Populations

TL;DR

This paper investigates how stellar rotation influences the ionizing spectra and overall properties of stellar populations, revealing that rotation results in harder radiation fields and increased luminosities, which are crucial for understanding distant galaxies.

Contribution

It introduces new synthetic stellar populations incorporating stellar rotation effects, highlighting their significant impact on population properties compared to non-rotating models.

Findings

Rotating stars produce harder ionizing radiation fields.

Rotational effects increase bolometric luminosity.

Rotation alters lifetimes, temperatures, and mass loss rates of massive stars.

Abstract

We present a sample of synthetic massive stellar populations created using the Starburst99 evolutionary synthesis code and new sets of stellar evolutionary tracks, including one set that adopts a detailed treatment of rotation. Using the outputs of the Starburst99 code, we compare the populations' integrated properties, including ionizing radiation fields, bolometric luminosities, and colors. With these comparisons we are able to probe the specific effects of rotation on the properties of a stellar population. We find that a population of rotating stars produces a much harder ionizing radiation field and a higher bolometric luminosity, changes that are primarily attributable to the effects of rotational mixing on the lifetimes, luminosities, effective temperatures, and mass loss rates of massive stars. We consider the implications of the profound effects that rotation can have on a stellar population, and discuss the importance of refining stellar evolutionary models for future work in the study of extragalactic, and particularly high-redshift, stellar populations.