Rotational studies of late-type stars. I - Rotational velocities of solar-type stars

The present investigation has the objective to obtain good rotational velocities for a large sample of solar-type stars, primarily for the purpose of discussing angular momentum loss. A demonstration is provided of the technique of line profile modeling, and the factors which contribute to uncertainty at small v sin i's are examined. The excellent fits which can be made to solar data using simple models indicate that systematic errors associated with the line modeling process are negligible. Such fits to the sun are essential for ensuring reliable results for slow rotators. The technique of profile modeling can discern differences in v sin i of less than 0.3 km/s for stars rotating as slowly as the sun if the data are of very high quality.