2004ApJ...614..211S

We have observed the massive star-forming region associated with the early B protostar G192.16-3.84 in NH₃(1, 1), 22.2 GHz H₂O masers, 1.3 cm continuum emission, and at 850 µm. The dense gas associated with G192.16 is clumpy, is optically thin, and has a mass of 0.9 M_☉. The NH₃ core is gravitationally unstable, which may signal that the outflow phase of this system is coming to an end. Water masers trace an ionized jet 0".8 (1600 AU at a distance of 2 kpc) north of G192.16. Masers are also located within 500 AU of G192.16; their velocity distribution is consistent with but does not strongly support the interpretation that the maser emission arises in a 1000 AU rotating disk centered on G192.16. Roughly 30" south of G192.16 (0.3 pc) is a compact, optically thick (τ=1.2) NH₃core (called G192 S3) with an estimated mass of 2.6 M_☉. Based on the presence of 850 µm and 1.2 mm continuum emission, G192 S3 probably harbors a very young, low-mass protostar or protocluster. The dense gas in the G192 S3 core is likely to be gravitationally bound and may represent the next site of star formation in this region.