A fragmentation-coalescence model for the initial stellar mass function

The authors have derived the initial stellar mass function (IMF), taking into account both effects of fragmentation of the gas clouds and coalescence among the fragments themselves. For fragmentation Silk's scenario is adopted, i.e., protostars formed in a parent cloud establish a mean field of radiation which interacts with grains to heat the gas. The maximum mass of stars is determined by the constraint that the local Jeans length should be smaller than the mean separation among preexisting protostars. The effects of coalescence upon the resulting mass spectrum are studied. If one assumes L(m) ∝ m³ for protostars, a Salpeter-like initial stellar mass function is obtained, whereas for L(m) ∝ m1.5, the resulting slope of the IMF becomes nearly flat.