AdvancedStarForm · Global and local star formation with state-of-the-art physics

Global and local star formation with state-of-the-art physics

Stars are the building blocks, the fundamental units of luminous matter in the universe, and they are responsible, directly or indirectly, for most of what we see when we observe it. It is thus of central importance to understand how stars form and what determines their properties. Many observational campaigns are today focusing on proto-planetary systems, and it is of paramount importance to develop new generations of theoretical models of star/planet formation and evolution, which can predict observable properties of proto-planetary systems, with obvious consequences for the understanding of our own solar system. New stars form within large turbulent complexes, harboring several thousands of solar masses of cold gas: the giant molecular clouds. The gas fragments and collapses gravitationally, then heats up via compression until temperatures exceed the nuclear fusion ignition point and the star is born. Computational modeling is very challenging, as large-scale environmental factors couple to small-scale processes close to the star, connecting many physical mechanisms, including magnetic fields, gravity, radiation, and chemistry. The project aims to construct a unified description of star formation, from large to small scales, using the world’s most advanced numerical physics. A two-way approach was used. First, I performed global simulations of giant molecular clouds to study star formation in a global context. I also worked to devise a new model for representing unresolved stars in global models, based on a large set of stellar structure calculations. The local approach focussed on an individual proto-planetary system, resolving all the scales down to the stellar surface (see image “The scales of star formation”). The fast rotation of the star and its envelope creates an accretion disk around the star, and it is inside this disk that planets eventually form. One needs to carefully incorporate magnetic fields, radiation and chemistry, which are all linked together, as the absence of one or the other can mean that no disk or planets form at all.

Data: CORDIS, © European Union