Cool Stars 14 - Submitted Abstract # 289 This version created on 05 October 2006 Models fo Differentially Rotating, 1 -2 Solar Mass Main-Sequence Stars Keith MacGregor, HAO/NCAR Stephen Jackson, HAO/NCAR Andrew Skumanich, HAO/NCAR Travis Metcalfe, HAO/NCAR We present models for chemically homogeneous, differentially rotating, main-sequence stars with masses in the range from 1 to 2 solar masses. The models were constructed using a code based on a reformulation of of the self-consistent field method of computing the equilibrium stellar structure for a specified conservative internal rotation law. Relative to nonrotating stars of the same mass, these models all have reduced luminosities and effective temperatures, and flattened photospheric shapes (i.e., decreased polar radii) with equatorial radii that can be larger or smaller, depending on the degree of differential rotation. For a fixed ratio of the axial rotation rate to the surface equatorial rotation rate, increasingly rapid rotation generally deepens convective envelopes, shrinks convective cores, and can lead to the presence of a convective core (envelope) in a 1 (2) solar mass model, a feature that is absent in a nonrotating star of the same mass. The positions of differentially rotating models for a given mass in the H-R diagram can be shifted in such a way as to approximate the nonrotating ZAMS for lower mass stars. Implications of these results include (i) possible ambiguities arising from similarities between the properties of rotating and nonrotating models of different masses, (ii) a reduced radiative luminosity for a young, rapidly rotating Sun, (iii) modified rates of lithium destruction by nuclear processes in the layers beneath an outer convective envelope, and (iv) the excitation of solar-like oscillations and the operation of a solar-like hydromagnetic dynamo in some 1.5 - 2 solar mass stars. ----------------------------------