CoRoT observations of O stars: diverse origins of variability

TL;DR

This study uses CoRoT satellite data to analyze variability in six O-type stars, revealing diverse origins including pulsations, binarity, and rotational effects, with some stars showing signs of sub-surface convection.

Contribution

First detailed asteroseismic analysis of O stars using CoRoT data, identifying various variability mechanisms and potential sub-surface convection signatures.

Findings

Detection of low-amplitude pulsations in some O stars

Identification of binarity and rotational modulation effects

Evidence of red-noise possibly linked to sub-surface convection

Abstract

Six O-type stars were observed continuously by the CoRoT satellite during a 34.3-day run. The unprecedented quality of the data allows us to detect even low-amplitude stellar pulsations in some of these stars (HD 46202 and the binaries HD 46149 and Plaskett's star). These cover both opacity-driven modes and solar-like stochastic oscillations, both of importance to the asteroseismological modelling of O stars. Additional effects can be seen in the CoRoT light curves, such as binarity and rotational modulation. Some of the hottest O-type stars (HD 46223, HD 46150 and HD 46966) are dominated by the presence of red-noise: we speculate that this is related to a sub-surface convection zone.