A Submillimeter Study of the Star‐forming Region NGC 7129

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Abstract
New molecular (13CO J = 3-2) and dust continuum (450 and 850 μm) maps of the NGC 7129 star-forming region are presented. The maps include the Herbig Ae/Be star LkHα 234, the far-infrared source NGC 7129 FIRS 2, and several other prestellar sources embedded within the molecular ridge. The data are complemented with C18O J = 3-2 spectra at several positions within the mapped region. Both the submillimeter and the 13CO emission show a similar morphology, displaying a sharp boundary toward the cavity. The submillimeter maps also reveal a second source, SMM 2, which is not clearly seen in any earlier data set. This is either a prestellar core or possibly a protostar. Also, the highest continuum peak emission is identified with the deeply embedded source IRS 6 a few arcseconds away from LkHα 234. These new 450 and 850 μm observations are combined with previous continuum observations of the three compact far-infrared sources in the field, in order to make fits to the spectral energy distributions and to obtain the source sizes, dust temperatures, luminosities, and masses. For nine positions where both 13CO and C18O spectra are available, gas masses have been obtained and compared with masses derived from the continuum fluxes. The masses are found to be consistent, implying little or no CO depletion onto grains. The dust emissivity index is found to be low toward the dense compact sources, β ~ 1-1.6, and high, β ~ 2.0, in the surrounding cloud.