Far-infrared ISOPHOT observations and the energy balance of a quiescent globule

Abstract

We have observed a quiescent small globule, the Thumbprint Nebula, with the ISOPHOT far-infrared camera at 100 and 200mu m. The observed emission is optically thin thermal emission from dust at a temperature of ~ 14-16K. The energy budget of the cloud is studied by considering the energy input (interstellar radiation field, ISRF), and outputs (scattered and emitted radiation). It is found that the ISRF is sufficient to be the only heating source of dust in the cloud. We have derived values of absorption cross sections of dust at 100 and 200mu m, and found them to be in good agreement with current dust models. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with the participation of ISAS and NASA