Turbulent convection and pulsation stability of stars - III. Non-adiabatic oscillations of red giants

TL;DR

This paper models non-adiabatic oscillations in luminous red giants, revealing that low-order radial modes can be self-excited due to radiation and convection interactions, with turbulent pressure playing a key role.

Contribution

It introduces a non-local, anisotropic, time-dependent convection theory to analyze pulsations in red giants, highlighting the importance of turbulent pressure in mode excitation.

Findings

Low-order radial modes can be self-excited in red giants.

Radiation and convection coupling drive oscillation excitation.

Turbulent pressure significantly influences pulsation stability.

Abstract

We have computed linear non-adiabatic oscillations of luminous red giants using a non-local and anisotropic time-dependent theory of convection. The results show that low-order radial modes can be self-excited. Their excitation is the result of radiation and the coupling between convection and oscillations. Turbulent pressure has important effects on the excitation of oscillations in red variables.