Differential rotation models for late-type dwarfs and giants

A model for global circulation in outer stellar convection zones is applied to simulate the angular velocity dependence of differential rotation for t wo spectral classes, G2 and K5, of main-sequence dwarfs. Only the solar-typ e rotation laws with an increasing angular velocity from pole to equator an d a relatively small rotation inhomogeneity in radius were found. Different ial rotation for G2 is larger compared to K5, their angular velocities bein g equal. As the rotation period decreases from its solar value, the absolut e value of the surface differential rotation decreases initially but change s to a slight increase for periods of several days. The meridional flow ins ide the convection zones is confined to thin boundary layers at the top and bottom with a typical velocity amplitude of about 10 m s(-1). Also a seque nce of rotation laws for evolving 2.5M. star is produced. The predicted dif ferential rotation is solar-like in structure and super-solar in amplitude. A comparison with observations is made and implications for dynamo theory of stellar activity are briefly discussed.