Amplitudes of stochastically excited oscillations in main-sequence stars

We present estimates of the amplitudes of intrinsically stable stochastical ly excited radial oscillations in stars near the main sequence. The amplitu des are determined by the balance between acoustical energy generation by t urbulent convection (the Lighthill mechanism) and linear damping. Convectio n is treated with a time-dependent, nonlocal, mixing-length model, which in cludes both convective heat flux and turbulent pressure in both the equilib rium model and the pulsations. Velocity and luminosity amplitudes are compu ted for stars with masses between 0.9 M. and 2.0 M. in the vicinity of the main sequence, for various metallicities and convection parameters. As in p revious studies, the amplitudes are found to increase with stellar mass, an d therefore with luminosity. Amongst those stars that are pulsationally sta ble, the largest amplitudes are predicted for a 1.6 M. model of spectral ty pe F2; the values are approximately 15 times larger than those measured in the Sun.