Magnetic loops on rapidly rotating stars.

We present models for the thermal and mechanical equilibria of slender magnetic loops on rapidly-rotating stars. These loops are embedded within an arcade located on the stellar equator. The loop properties are governed principally by the specified base pressure and conductive flux. While rapid rotation is important in determining the pressure structure within the loop, its main effect on the loop shape is through its influence on the base values of magnetic field strength, pressure, and conductive flux. We have compared our models with observations of the temperatures and X-ray fluxes of stars with a range of rotation rates. By using the observed Variation of the differential emission measure with rotation rate Omega and allowing the base magnetic field strength to scale as B proportional to Omega(q) (q = 0.5, 0.75, 1.0) we can explain the variation of the temperature and X-ray flux of the slower rotators. For the most rapid rotators, however (approximately Omega/Omega. > 10) it appears that a single value of q for all rotation rates cannot explain the observations and some other mechanism is needed to explain the saturation in the Xray flux. We have also investigated the effect of using a heating function that is proportional to the density and one that falls off exponentially with height. With the parameters that we can calculate from these models it is not possible to discriminate between these two types of heating.