Massive star interiors revealed by gravity wave asteroseismology and high-resolution spectroscopy

TL;DR

This paper reviews how gravity wave asteroseismology and high-resolution spectroscopy reveal the internal structures of massive stars, focusing on stochastic low frequency variability caused by gravity waves and other mechanisms.

Contribution

It introduces methods and summarizes findings on SLF variability in massive stars, emphasizing the role of gravity waves in probing stellar interiors.

Findings

Gravity waves are key to explaining SLF variability.

SLF variability is linked to convective and turbulent processes.

Spectroscopy and photometry effectively study stellar interior dynamics.

Abstract

In recent years, it has been discovered that massive stars commonly exhibit a non-coherent form of variability in their light curves referred to as stochastic low frequency (SLF) variability. Various physical mechanisms can produce SLF variability in such stars, including stochastic gravity waves excited at the interface of convective and radiative regions, dynamic turbulence generated in the near-surface layers, and clumpy winds. Gravity waves in particular are a promising candidate for explaining SLF variability as they can be ubiquitously generated in main sequence stars owing to the presence of a convective core, and because they provide the large-scale predominantly tangential velocity field required to explain macroturbulence in spectral line fitting. Here, I provide an overview of the methods and results of studying SLF variability in massive stars from time series photometry and spectroscopy.