Evidence of High Excitation in the Herbig-Haro 111 Jet

s of recently accepted papers The L1448 Molecular Jet John Bally, Elizabeth A. Lada and Adair P. Lane 1 Department of Astrophysical, Planetary, and Atmospheric Sciences and Center for Astrophysics and Space Astronomy Campus Box 389, University of Colorado, Boulder, CO 80309 2 Harvard-Smithsonian Center for Astrophysics 60 Garden St., MS-42, Cambridge, MA 02138 3 Harvard-Smithsonian Center for Astrophysics 60 Garden St., MS-78, Cambridge, MA 02138 We have obtained near-infrared images of the L1448 molecular outflow in the J, H, and K bands and through a 1% passband filter centered on the 2.122μm v=1-0 S(1) line of molecular hydrogen. We report the discovery of a highly collimated, clumpy, and bipolar molecular hydrogen jet associated with the L1448 molecular outflow. We estimate that the total H2 luminosity of the L1448 outflow is about 0.2 L . Most of the line emission in the northern outflow lobe arises from a narrow, curving filament consisting of a chain of knots. Some H2 knots and the bow-shaped emission regions protruding several arcseconds to the west of the filament may be shocks associated with COand SiO-emitting “bullets” seen in mm-wave observations. We interpret the H2 emission in the context of a jet-driven model for molecular outflows. Bright H2 emission near the molecular “bullets” may be produced by shocks propagating into the moving medium, while the extended and curving filament may be driven by expanding bow shocks in the wakes of the “bullets”. A conical 2.2 μm continuum nebula extends from the driving source of the L1448 outflow towards the blueshifted outflow lobe. Several knots of H2 emission to the northeast of the main L1448 H2 filament may be associated with a separate outflow emerging from L1448 IRS 3, which we estimate has a total H2 luminosity of about 0.01 L . Accepted by Astrophysical Journal Evolution of the Solar Nebula. II. Thermal Structure During Nebula Formation