AAS Meeting #193 - Austin, Texas, January 1999
Session 73. Young Stars
Display, Friday, January 8, 1999, 9:20am-6:30pm, Exhibit Hall 1

## [73.01] The Disk and Outflow in G192.16: Are Massive Outflows and Accretion Disks Different from those in Low-Mass YSOs?

D. S. Shepherd (CalTech), S. Kurtz (Univ. Nacional Auton\'oma de M\'exico)

We present the discovery of a circumstellar disk around the luminous Young Stellar Object (YSO) G192.16-3.82. Observations of 2.6~mm, 7~mm, and 3.6~cm continuum emission and 13CO, C18O, and H2O maser line emission using the Owens Valley Radio Observatory and the Very Large Array reveal a 1000~AU, rotating disk around the central B2 star. The mass of the disk plus envelope is ~ 20~M\odot. The YSO is embedded in a 500~M\odot molecular cloud from which a massive outflow emerges. Updated outflow parameters yield a total flow mass of 95~M\odot and a mass flow rate of 5.6 \times 10-4~M\odot~yr-1. The outflow opening angle, defined by a 13CO shell centered on the YSO, is ~ 90\circ. There is no evidence for the presence of a collimated jet, thus, the massive outflow is most likely produced by a powerful, moderately collimated wind with sufficient momentum to create a flow that is greater than 10~pc from end-to-end with ~10 times the mass of the central star. Approximately 0\farcs5 to the north of the massive G192.16 YSO and disk is a stripe of 3.6~cm continuum emission along with red-shifted H2O maser components which we interpret to be due to a jet emanating from a newly discovered YSO, G192.16~N. This jet/outflow system does not appear to significanty affect the dynamics of the massive outflow, hence, it is probably due to a low-mass YSO.