On the Origin of the Heavy Elements.

The present paper is an attempt to explain the formation of heavy elements and to trace the astro- nomical consequences of the results obtained from such a study. In Section I the problem is stated, and the general outline for a possible solution is indicated. Section II deals with the d~scussion of the expres- sion for the energy content of atomic nuclei. The resulting formula represents the observational data as well as can be expected. In Section III this formula is used to find what kind of nucleus is most stable under different conditions of density. It appears that, when the electron gas is degenerate, nuclei of large atomic weight may be formed. A small correction of the original formula, which is required by theory and which does not con- ffict with observational data, allows the formation of nuclei up to atomic weight 240 and higher. In Section IV the astronomical consequences of the theory are discussed. It appears that the only favorable places for the formation of heavy nuclei are the interiors of massive stars, which cannot become regular white dwarfs on account of their relatively high masses. When these stars contract to very high densities, rotation begins to counterba1anc~e gravity, and under certain conditions matter ih their in- teriors will cool and become degenerate. This is the state at which the formation of heavy elements be- gins. The process results ultimately in an explosion, which distributes part of the heavy elements over the surrounding space and leaves one or more stellar remnants in the form of white dwarfs. In Section V the problem of the formation of the light elements is touched. Since not every massive star can be expected to develop a degenerate core, the formation of the lighter elements may be explained as a result of thermonuclear reactions at temperatures of the order of 1O~ degrees. Section VI deals with the possible observational evidence. Actual calculation of stellar models must be made in order to identify the different phenomena described with existing stars and thus provide ob- servational checks