Dense cores in the Orion molecular cloud

We have used the Heinrich Hertz submillimeter telescope to measure the J = 3-2 and J = 2-1 lines of (CO)-C-12-O-16 and (CO)-C-12-O-18, and the J = 3-2 line of (CO)-C-13-O-16 toward 125 high-density cores in the prominent S-sh aped feature in L1640. We have also measured the (J, K) = (1, 1) and (2, 2) inversion transitions of NH, from these sources. These results have been u sed to determine kinetic temperatures, H-2 densities, and column densities. Estimates of the stability of these cores are made. Comparisons are also m ade with other nearby star formation regions such as the Taurus clouds. Sou rces in the northern part of the region surveyed have larger line widths, k inetic temperatures, T-k, and higher ratios of the J = 3-2 to J = 2-1 lines of (CO)-O-18. It is likely that these sources are heated externally. Excep t for cores in the southern part of this cloud, T-k exceeds 10 K, the value found for dark dust clouds. The average density for all cores is similar t o 3 x 10(4) cm(-3). Orion KL is an extraordinary source, with much larger T -k, local density, and column density than any other source in our sample.