Program: GS-2013A-Q-12

Title:Untangling the protostars and jets in HH 900
PI:Megan Reiter
Co-I(s): Nathan Smith

Abstract

We propose to obtain high resolution (comparable to HST), narrowband [Fe II] images with GSAOI to disentangle the protostars and jets in HH 900. Recent H-alpha imaging of HH 900 reveals an unusually broad outflow emerging from a small (~1"), dark globule in Trumpler 16. A bright H-alpha microjet along the western edge of HH 900 may be a second jet-protostar system that was ejected from the dark globule. Strong UV radiation from the many O stars in Trumpler 16 illuminates unshocked material in these jets, making it possible to estimate the jet mass-loss rates and infer the mass accretion history of the driving protostars. Two Spitzer-detected YSOs appear to lie within the globule, although with relatively coarse resolution (2"), Spitzer cannot resolve which protostar drives the jet. However, for HH jets with an associated Spitzer source, we have shown that IR [Fe II] emission traces the jet into the dark globule, connecting the H-alpha jet with the driving protostar. In addition, [Fe II] in these externally irradiated jets is excited in the dense, neutral jet core and may trace most of the mass in the outflow. We also propose to obtain narrowband H_2 images of HH 900 to see if extended H2 emission seen in ground-based images without AO correction corresponds to molecules entrained in the outflow. The associated Spitzer YSOs suggest that HH 900 samples the lower mass end of the jet-driving protostars detectable in Carina. Previous studies of [Fe II] in HH jets in Carina have focused on bright, highly collimated outflows likely driven by more massive, and more evolved protostars. Thus, HH 900 provides an important test of the behavior of lower mass jet driving protostars. These observation will be a chapter in P.I. M. Reiter's PhD thesis.

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