SIMBAD references

Interstellar gas comes with empirical physical relations governing mean parameters such as the gas density n, diameter D, magnetic field B, and gas line width σ, with the forms <n>~D^c, <B>~<D>^p, <B>~<n>^k, <σ>~<D>^q, and p=ck. Using these results, I derive simple formulae for the energy components in turbulent young stellar objects of Classes 0 and I as a function of clump size D (D<0.5 pc) from empirical fits to observations. Here I find the relative importance of the energy components in molecular clumps, each one of the form <E>~D^x, with x ranging from 0 to 3. Magnetic and gravitational energies are more important for small D (<0.1 pc), while for large D (>0.1 pc) turbulent and gravitational energies become dominant (x=2). In addition, the expected relationship between turbulent width and magnetic field, <σ>~<B>^q/p^, is not steep, and the observational data to date bear this out. Damping scenarios, magnetic field shapes, and ambipolar diffusion relevant to observations are discussed.