A HIGH SPATIAL RESOLUTION STUDY OF THE λ = 3 mm CONTINUUM OF ORION-KL

Recent interferometric observations have called into question the traditional view of the Orion-KL region, which displays one of the most well-defined cases of chemical differentiation in a star-forming region. Previous lower-resolution images of Orion-KL show emission signatures for oxygen-bearing organic molecules toward the Orion Compact Ridge and emission for nitrogen-bearing organic molecules toward the Orion Hot Core. However, more recent observations at higher spatial resolution indicate that the bulk of the molecular emission arises from many smaller, compact clumps that are spatially distinct from the traditional Hot Core and Compact Ridge sources. It is this type of observational information that is critical for guiding astrochemical models, as the spatial distribution of molecules and their relation to energetic sources will govern the chemical mechanisms at play in star-forming regions. We have conducted millimeter-imaging studies of Orion-KL with various beam sizes using the Combined Array for Research in Millimeter-Wave Astronomy in order to investigate the continuum structure. These λ = 3 mm observations have synthesized beam sizes of ∼0.″5–5.″0. These observations reveal the complex continuum structure of this region, which stands in sharp contrast to the previous structural models assumed for Orion-KL based on lower spatial resolution images. The new results indicate that the spatial scaling previously used in determination of molecular abundances for this region are in need of complete revision. Here we present the results of the continuum observations, discuss the sizes and structures of the detected sources, and suggest an observational strategy for determining the proper spatial scaling to accurately determine molecular abundances in the Orion-KL region.