Astrophysical APL - diamonds in the sky

Abstract

Computational astrophysics seeks to develop numerical models which help elucidate the nature of astronomical systems. Such models must not only adequately describe the underlying physics which give rise to phenomena that have been observed, but must also be predictive in asserting what future observations might unfold. Any model which is in conflict with physical observations, clearly, must be discarded or amended to reflect reality. As a computational modelling tool we find APL useful for testing astrophysical hypotheses, and extending the domain of our observationally based knowledge. Using APL to build, test, and expand astrophysical models frees the investigator from the mechanical drudgery of computer programming, thereby allowing the researcher to concentrate on understanding the physical universe.As a quantitative example of how relatively complex astrophysical phenomena can be explored with ease using APL, we have developed a structure model for white dwarf stars. The model presented here considers such effects as Coulomb interactions between electrons and nucleons, inverse beta decays, and the effects of the general theory of relativity on the condition of hydrostatic equilibrium. This structure model is valid for zero-temperature stars of varying chemical compositions, ionic partitions, and central densities; and is applicable over a wide range of partial and total degeneracy regimes.