Question

Calculate the minimum mass at which gravity and pressure balance for a cloud composed only of hydrogen and helium that cannot cool below 100k. Assume that density is the same, 300 particles per cubic centimeter, as molecular clouds in the Milky way (give the answer in both solar masses in kg).

Answer 1

the characteristics of a typical molecular cloud pretty well: it is very large (containing several hundred thousand solar masses of material) and very cold (only about 10 K). The gas within has a density of over 1,000 molecules per cubic centimeter, much higher than the average in interstellar space. The combination of high density and low temperature means that any clumps which may form within the cloud are liable to start collapsing under their own self-gravity. Indeed, when we look closely at molecular clouds, we find that they are full of such clumps, often called "cores"; and within the cores, new stars are being born.a "runaway process." In regions of high-mass star formation, a collapsing core fragments into many pieces, each of which continues to collapse on its own. The collapse will continue until something raises the temperature of the gas enough that the gas pressure balances the gravitational force