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Sep 24 |
Taft Armandroff
Director, McDonald Observatory |
"Discussion: Ideas for McDonald Observatory's submission of a Whitepaper, in response to the National Research Council's Committee's call for a Whitepaper on 'The Strategy to Optimize the US Optical and Infrared (OIR) System in the Era of the Large Synoptic Survey Telescope (LSST)' "
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Oct 8 |
Tanja Rindler-Daller
University of Michigan |
"Dark Stars: Evolution and First Pulsation Results"
The study of the first stars in the Universe is an active field in Astrophysics and Cosmology with numerous implications, ranging from reionization and galaxy formation to metal enrichment and the impact on subsequent stellar generations. Among the first stars to form may be "dark stars", i.e. stars of primordial composition, but powered by the heating released in the process of dark matter (DM) particle self-annihilation. This same process of DM self-annihilation is responsible for the correct relic density of DM today. It has been shown that a DM-powered stellar phase is feasible, due to the high DM densities in the centers of primordial minihalos and the efficiency of DM annihilation. DM could thereby be responsible for an entirely new class of stellar objects, while possible detection of the latter would provide a smoking gun for DM. Previous investigations have found that DM-powered dark stars could become very massive (M > 10^5 M_solar), bright, cool and puffy objects. Once these supermassive dark stars run out of DM fuel, they collapse and could be forming the seeds for the supermassive central black holes which are observed in nearby and high-redshift galaxies.
We have used the stellar evolution code MESA in order to improve upon previous stellar models, which were limited to polytropic equilibria, and to address several key issues of dark star astrophysics, including the first results on p-mode pulsations of dark stars. Apart from presenting our own results, I will give a general overview over the dark star proposal, its motivations and implications, as well as the challenges involved. Also, I will talk about the prospects of observing dark stars with upcoming space telescopes.
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