Amplitudes of stochastically excited oscillations in main-sequence stars

TL;DR

This paper estimates the amplitudes of stochastically excited oscillations in main-sequence stars, considering turbulent convection and damping, and predicts amplitudes across different stellar masses and metallicities.

Contribution

It introduces a detailed model for oscillation amplitudes in stars near the main sequence, incorporating nonlocal convection and turbulent pressure effects.

Findings

Amplitude increases with stellar mass and luminosity.

Maximum predicted amplitudes are for a 1.6 M_sun F2 star.

Predicted amplitudes are about 15 times larger than solar measurements.

Abstract

We present estimates of the amplitudes of intrinsically stable stochastically excited radial oscillations in stars near the main sequence. The amplitudes are determined by the balance between acoustical energy generation by turbulent convection (the Lighthill mechanism) and linear damping. Convection is treated with a time-dependent, nonlocal, mixing-length model, which includes both convective heat flux and turbulent pressure in both the equilibrium model and the pulsations. Velocity and luminosity amplitudes are computed for stars with masses between 0.9 M_\sun and 2.0 M_\sun in the vicinity of the main sequence, for various metallicities and convection parameters. As in previous studies, the amplitudes are found to increase with stellar mass, and therefore with luminosity. Amongst those stars that are pulsationally stable, the largest amplitudes are predicted for a 1.6 M_\sun model of spectral type F2; the values are approximately 15 times larger than those measured in the Sun.