A low density molecular cloud in the vicinity of the Pleiades.

The central region of a small, low density molecular cloud, which lies to the south of the Pleiades cluster, has been studied through the use of molecular line observations. Column densities for CH, OH, (C-12)O, and (C-13)O are derived from the radio data. The CH and OH data yield a visual extinction through the center of the cloud of about 3 mag. The ratio of the antenna temperatures for the OH main lines is consistent with optically thin emission; therefore, the OH results are a good indication of the total extinction through the cloud. The analysis of the carbon monoxide data produces a relatively high kinetic temperature of at least 20 K a low total gas density of about 300-500 per cu cm, and a column density of about 4 x 10 to the 17th per sq cm for (C-12)O. Thus this small molecular cloud is not typical of the molecular material generally studied in Taurus.