Dept. of Earth and Space Sciences, Chalmers University of Technology, Gothenburg

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Phone +46 (0)768 99 977794

Website: http://www.chalmers.se/sv/personal/Sidor/hans-olofsson.aspx

Hans Olofsson is studying processes that are relevant for the birth and death of stars. During the last years he has mainly focussed on the latter subject.

Stars live a very active life at the end of their life cycle. During the last stage they lose significant amounts of matter in the form of an intense stellar wind. The ejected material is enriched in elements (such as carbon, nitrogen, oxygen, etc.) and in this way the stars contribute to the elemental synthesis, a necessary condition for life to emerge.

The mass loss may be large enough that stars with initial masses as high as ten times that of the sun avoid exploding as a supernova. Instead they die peacefully as a white dwarf. During a brief period such a white dwarf is surrounded by a large, glowing gas envelope, a planetary nebula, one of the most spectacular phenomena in the astronomical sky. Our sun will go through this final evolution in about seven billion years.

Hans Olofsson has performed extensive studies of the physical and chemical properties of the ejected gas through multi-method observations and numerical simulations. The aim is to understand the final evolution that the majority of the stars in the universe go through, and also how this affects the chemical evolution of galaxies.