Observations of α Orionis, R Aquilae, and R Aquarii at 14.9 GHz

We have measured the 14.9-GHz continuum flux densities of the M-type stars α Ori, R Aql, and R Aqr. For α Ori and R Aql it is suggested that the emission at this frequency is primarily due to ionized gas associated with stellar chromospheres or coronae. For R Aqr we propose a model consistent with available data, in which the variable intensity of the radio emission depends on a variable mass loss rate for the Mira