Excitation of Radial P-Modes in the Sun and Stars

P-mode oscillations in the Sun and stars are excited stochastically byReynolds stress and entropy fluctuations produced by convection in theirouter envelopes. The excitation rate of radial oscillations of starsnear the main sequence from K to F and a subgiant K IV star have beencalculated from numerical simulations of their surface convection zones.P-mode excitation increases with increasing effective temperature (untilenvelope convection ceases in the F stars) and also increases withdecreasing gravity. The frequency of the maximum excitation decreaseswith decreasing surface gravity.