Radio continuum-H2O maser systems in NGC 2071: H2O masers tracing a jet (IRS 1) and a rotating proto-planetary disk of radius 20 AU (IRS 3)

We have observed simultaneously the 1.3 cm continuum and H2O maser emission toward the core of the star-forming region NGC 2071 using the Very Large A rray in its A configuration. Two 1.3 cm continuum sources have been detecte d in the region, coinciding with the infrared sources IRS 1 and IRS 3, resp ectively. The radio emission in IRS 3 is consistent with an ionized thermal bipolar radio jet. Two clusters of H2O maser spots are detected, one assoc iated with IRS 1 (22 spots) and the other one associated with IRS 3 (13 spo ts). The H2O maser distribution in IRS I seems to be tracing at scales of 3 00 AU the larger scale H-2 outflow observed at a few thousands of AU from t he exciting source. On the other hand, the H2O masers in IRS 3 are distribu ted as an apparent disk of similar or equal to 0." 05 (similar or equal to 20 AU) radius, oriented almost perpendicular to the major axis of the radio jet. There is a clear velocity gradient (similar or equal to 0.35 km s(-1) AU(-1)) along the major axis of the H2O maser distribution, which can be g ravitationally bound by a central mass of similar or equal to 1 M-.. These results, together with the low-mass and early evolutionary stage of IRS 3, suggest that masers around this source are tracing a rotating proto-planeta ry disk within a proto-solar-like system. This represents direct kinematic evidence of the smallest rotating circumstellar disk ever observed around a young stellar object (YSDO). We discuss the dichotomy of H2O masers tracin g either outflows or disks around YSOs, based on the evolutionary scheme pr oposed in our earlier work. We suggested that systems in which H2O masers t race disks are less evolved than those in which masers trace outflows. In t his scheme, IRS 3 would then represent a relatively less-evolved object tha n IRS 1. This prediction is consistent with independent infrared observatio ns showing that IRS 3 is at an earlier phase of evolution.