Photoevaporation is probably the main agent for gas dispersal during the last stages of protoplanetary disk evolution .
However , the overall mass loss rate in the photoevaporative wind and its driving mechanism are still not well understood .
Here we report multi-configuration Very Large Array observations at 0.7 , 3 , and 5 cm towards the transitional disk of GM Aur .
Our radio continuum observations allow us to image and spatially resolve , for the first time , the three main components at work in this stage of the disk evolution : the disk of dust , the ionized radio jet perpendicular to it , and the photoevaporative wind arising from the disk .
The mass loss rate inferred from the flux density of the radio jet is consistent with the ratio between ejection and accretion rates found in younger objects , suggesting that transitional disks can power collimated ejections of material apparently following the same physical mechanisms as much younger protostars .
Our results indicate that extreme-UV ( EUV ) radiation is the main ionizing mechanism of the photoevaporative wind traced by the free-free emission .
The required low EUV photon luminosity of \sim 6 \times 10 ^ { 40 } s ^ { -1 } would produce a photoevaporation rate of only \dot { M } _ { w,EUV } \simeq 1.3 \times 10 ^ { -10 } ~ { } M _ { \odot } yr ^ { -1 } .
Therefore , other mechanisms are required to disperse the disk in the timescale imposed by observations .