We report the detection of thermal continuum radio emission from the K0 III coronal giant Pollux ( \beta Gem ) with the Karl G. Jansky Very Large Array ( VLA ) .
The star was detected at 21 and 9 GHz with flux density values of 150 \pm 21 and 43 \pm 8 \mu Jy , respectively .
We also place a 3 \sigma _ { \mathrm { rms } } upper limit of 23 \mu Jy for the flux density at 3 GHz .
We find the stellar disk-averaged brightness temperatures to be approximately 9500 , 15000 , and < 71000 K , at 21 , 9 , and 3 GHz , respectively , which are consistent with the values of the quiet Sun .
The emission is most likely dominated by optically thick thermal emission from an upper chromosphere at 21 and 9 GHz .
We discuss other possible additional sources of emission at all frequencies and show that there may also be a small contribution from gyroresonance emission above active regions , coronal free-free emission and free-free emission from an optically thin stellar wind , particularly at the lower frequencies .
We constrain the maximum mass-loss rate from Pollux to be less than 3.7 \times 10 ^ { -11 } M _ { \odot } yr ^ { -1 } ( assuming a wind terminal velocity of 215 km s ^ { -1 } ) , which is about an order of magnitude smaller than previous constraints for coronal giants and is in agreement with existing predictions for the mass-loss rate of Pollux .
These are the first detections of thermal radio emission from a single ( i.e. , non-binary ) coronal giant and demonstrate that low activity coronal giants like Pollux have atmospheres at radio frequencies akin to the quiet Sun .