Jena 2013 – wissenschaftliches Programm

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SYNU: Symposium Numerik

SYNU 1: Numerik

SYNU 1.2: Hauptvortrag

Donnerstag, 28. Februar 2013, 17:00–17:30, HS 2

Challenges in Numerical Astrophysics: Modeling the Formation of Stars — •Ralf Klessen — Zentrum für Astronomie der Universität Heidelberg

Many recent developments in theoretical astrophysics are driven by advances in numerical simulation techniques and by the ever improving capabilities of modern supercomputers. I will discuss some of the challenges in the field that result from the intrinsic multi-scale and multi-physics nature of the processes that govern the formation and evolution of cosmic structures. I will focus on the physical processes that initiate and regulate the birth of stars in the early Universe as well as in galaxies such as our Milky Way today. Stars form by gravoturbulent fragmentation of interstellar gas. The supersonic turbulence ubiquitously observed in the Galaxy generates strong density fluctuations with gravity taking over in the densest and most massive regions. Collapse sets in to build up stars and star clusters. Turbulence plays a dual role. On global scales it provides support, while at the same time it can promote local collapse. This process is modified by the thermodynamic response of the gas, which depends on the intricate interplay between various heating and cooling processes. To model the dynamical evolution of the interstellar medium, it is necessary to couple the equations of magnetohydrodynamics with time-dependent chemistry and at the same time follow the interaction with the interstellar radiation field. To do so fully consistently is beyond our current capabilities, so the search for acceptable and computationally feasible approximations is an essential ingredient of modern computational astrophysics.