DUST AND MOLECULAR-PROPERTIES OF THE LOW-OPACITY CLOUD LYNDS-1563

Optical, molecular, and far-infrared data are analyzed for L1563, estimated peak A(b) 2.5 mag. The cloud is detected by IRAS at 12, 25, 60, and 100-mu-m, and with CO, (CO)-C-13, and H2CO molecules. A column density comparison yields an estimate of the temperature of the classical dust grains of 15.6 K (+/- 1 K), while the color temperature derived from the ratio I(60)/I(100) is 26 K. Both dust and color temperatures decrease toward the cloud center. (CO)-C-13 and H2CO spectral lines are detected above a threshold in I(100). I(12) and I(25) increase with I(100) only in the outer regions of the cloud. The ratio of (CO)-C-13/(CO)-C-12 integrated intensity rises toward the cloud center by 10.