Star Formation in Clouds of Molecular Hydrogen

Abstract

It is shown that the formation of hydrogen molecules on the surfaces of grains in interstellar clouds results in pressure instabilities leading to fragmentation of the clouds and the formation of protostars. The frequency distribution of the masses of stars thus formed (the initial mass function) is determined by the physical properties of interstellar grains and the density distributions in interstellar clouds; it has been calculated and agrees with observation. The rate of star formation is controlled by the rate of cosmic expansion; this has also been calculated and is consistent with observational data. Using the properties of this process of star formation, together with available data on the evolution of stars, supernovae and supermassive objects and the synthesis of elements and the formation of grains, calculated properties of model galaxies are shown to agree with observation. The evolution of galaxies is controlled by specific negative feedback loops. The properties of elliptical galaxies are found to be due to overshoot in the rate of star formation due to a slightly colder than average initial environment. The calculations contain no free parameters. The results are the inevitable consequence of the physical properties of solid grains, molecule formation and the cosmic expansion.