Protostellar condensations within the Orion ridge

Aperture synthesis observations of the CS J = 2 to 1 line and 95 GHz continuum emission from a 2 arcmin x 3 arcmin region around IRc2 in the OMC-1 molecular cloud have been obtained at 7.5 arcsec resolution with the Owens Valley Radio Observatory millimeter interferometer. These observations reveal four distinct condensations with the OMC-1 molecular ridge. The condensations lie along the edge of the bright central part of the H II region, M 42, suggesting that they may have been formed as a result of shock compression driven by the H II region. Their masses and densities, M about 50 solar masses and n about 10 to the 6th - 10 to the 7th/cu cm, suggest that the condensations will undergo further massive star formation on a short time scale (about 20,000 yr). 20 references.