0 A Submillimeter Study of the Star - Forming Region NGC 7129

We present new molecular (CO J=3−2) and dust continuum (450 μm and 850 μm) maps of the NGC7129 star forming region. The maps include the Herbig Ae/Be star LkHα 234, the far-infrared source NGC 7129 FIRS2 and several other pre-stellar sources embedded within the molecular ridge. We also obtained CO J=3−2 spectra at several positions within the mapped region. Both the continuum and CO emissions show a similar morphology, displaying a sharp boundary towards the cavity. A new protostar (SM2) is revealed in the continuum maps, not clearly seen in any earlier data set. Also, we are able to identify the highest peak emission with the deeply embedded source IRS6, a few arcseconds away from LkHα 234. Combining these new continuum observations with previous observations of the three compact far-infrared sources in the field, we make fits to the spectral energy distributions to obtain their sizes, dust temperatures, luminosities, and masses. For nine positions where we have CO spectra, we obtain gas masses and compare with masses derived from the continuum fluxes. The masses are found to be consistent, implying little or no CO depletion onto grains. A map of the 850μm/450μm spectral index, α, shows a correlation between α minima and the continuum flux peaks. The dense compact sources have dust emissivity indices, β, of 1 to 1.6, while β is typically 2.0 in the surrounding cloud. The spectral index, α, increases steeply from the center of the molecular ridge, through the PDR, to the molecular cloud boundary. Although an increase in temperature will contribute to an increase in α, the observed values require a rising β through the PDR. Subject headings: ISM: dust, molecules – submillimeter – stars: formation, pre-main sequence – stars: individual: LkHα 234