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First Stars III
Contact:
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Poster
Title: How Efficient is Rotational Mixing in Massive Stars? Author(s): Ines Brott Abstract: The VLT-Flames Survey for Massive Stars provides precise measurements of rotational velocities and nitrogen surface abundances of massive stars in the Magellanic Clouds. Specifically, for the first time, such abundances has been estimated for stars with significant rotational velocities. This extraordinary dataset gives us the unique possibility to calibrate rotationally and magnetically induced mixing processes. Therefore, we have computed a grid of stellar evolution models varying in mass, initial rotational velocity and chemical composition. In our models we find that although magnetic fields are essential to understand the internal angular momentum transport (and hence the rotational behavior), the mixing introduced by magnetic fields (namely the Kink instability) must be neglected to reproduce the observations. Further we show that for low metallicities detailed initial abundances are of prime importance, as solar-scaled abundances may result in significant calibration errors.
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