Zooming into the Collimation Zone in a Massive Protostellar Jet

Protostellar jets have a fundamental role at the earliest evolution of protostars all masses. In case low-mass (<8 Msun) protostars, strong observational evidence exists that launching and collimation is due to X- and/or disk-wind mechanisms. these models, it protostar/disk system creates necessary conditions launch collimate near protostar via magnetic fields. The origin from more massive has been investigated much less, in part because difficulty resolving zone distant objects. Here we present highest angular resolution observations jet powered by protostar, Cep A HW2 radio jet. We imaged emission projected distances only ~20 au innermost 100 protostellar for first time. morphology this object very different than what usually observed protostars. found outflowing material two components: wide-angle wind launched system, highly collimated starting 20-30 protostar. discuss possible scenarios: an extension classical or external wind. These results important consequences our understanding how stars masses are formed.