On the nature of the molecular cores in high-latitude cirrus clouds. II - Structure, stability, and physical conditions from CO-18) observations

Extensive observations of the J=2-1 and 1-0 lines of C 18 O, 13 CO, and 12 CO have been made of 33 high-latitude cirrus cloud cores and two high-latitude, cold, dense molecular clouds. It is argued that C 18 O is an essential observational tool for the understanding of molecular cloud structure. We have developed the formalism of molecular clouds both in polytropic hydrostatic equilibrium and also undergoing self-similar dynamical collapse, and we apply these to our C 18 O observations