Brightness temperatures for six solar-type stars at wavelengths from 0.5 mm to 6 cm (see the text). Detections were obtained below 1 cm and merely upper limits above that wavelength. The color coding and stellar identifications are given in the upper left corner of the figure. The open circles denote estimates of future ATCA detections of α Cen AB in 12 h at 20 and 6 GHz, respectively (see the text).