Spitzer reveals what’s behind Orion’s Bar

We present Spitzer Space Telescope observations of 11 regions in the Orion Nebula all southeast of the Bright Bar. Our Cycle 5 program obtained deep spectra with both the IRS short-high (SH) and long-high (LH) modules with aperture grid patterns chosen to very closely match the same area in the nebula. Previous IR missions observed only the inner few arcmin (the ‘Huygens’ region). The extreme sensitivity of Spitzer in the 10-37 μm spectral range permitted us to measure many lines of interest to much larger distances from the exciting star θ1 Ori C.