The IACOB project. VII. The rotational properties of Galactic massive O-type stars revisited

TL;DR

This study analyzes the rotational velocities of over 400 Galactic O-type stars, comparing empirical data with evolutionary models to understand their formation, evolution, and binary interactions.

Contribution

It provides a comprehensive overview of the rotational velocity distribution of Galactic O-type stars, incorporating spectroscopic and binary data, and compares findings with advanced evolutionary models.

Findings

Distribution of projected rotational velocities varies with mass and evolutionary stage.

Binary interactions influence the rotational velocity distribution.

Initial velocity distribution of massive stars is constrained by the data.

Abstract

Stellar rotation is of key importance for the formation process, evolution, and final fate of massive stars. In this paper we review results from the study of the spin rate properties of a sample of more than 400 Galactic O-type stars surveyed by the IACOB and OWN projects. By combining vsini, Teff, and logg estimates (resulting from a detailed quantitative spectroscopic analysis) with information about the spectroscopic binarity status for an important fraction of the stars in the sample, we provide a renewed overview about how the empirical distribution of projected rotational velocities in the O-star domain depends on mass, evolutionary and binary status. The obtained distributions are then compared with predictions of several state-of-the-art evolutionary models for single stars, as well as from population synthesis simulations including binary interaction, and used to provide hints about the initial velocity distribution of stars with masses in the range ~15-80 Msol.