The Stability and Thermal Properties of the Dark Cloud L 134
Xu Lanping(The Department of Geophysics, Peking University)
Using the results of optical observations and molecular line observations of the dark cloud L134, some basic physical parameters of the cloud are obtained and the stability and energy of the cloud are discussed.It is found that thermal pressure and rotation of the cloud are unimportant, while internal magnetic field may be more effective for supporting .the cloud against gravitational collapse. And the cloud could not collapse on the free-fall time scale but on a longer time scale of am-bipolar diffusion.The cooling and heating rates .in L134 are also calculated. The results show that the work done by the gravitation against thermal pressure is not an effective heating source, cosmic rays, however, may provide as much as about 20% heating energy required in L134. Calculation shows that internal magnetic energy released through the processes of ambipolar diffusion can supply the most part of energy required in LI 34, therefore it may be an excellent heat source.