On the origin of the chemical bimodality of disc stars: a tale of merger and migration

  title={On the origin of the chemical bimodality of disc stars: a tale of merger and migration},
  author={Tobias Buck},
  journal={Monthly Notices of the Royal Astronomical Society},
  • T. Buck
  • Published 19 September 2019
  • Physics
  • Monthly Notices of the Royal Astronomical Society
The Milky Way's stellar disk exhibits a bimodality in the [Fe/H] vs. [$\alpha$/Fe] plane, showing a distinct high-$\alpha$ and low-$\alpha$ sequence whose origin is still under debate. We examine the [Fe/H]-[$\alpha$/Fe] abundance plane in cosmological hydrodynamical simulations of Milky Way like galaxies from the NIHAO-UHD project and show that the bimodal $\alpha$-sequence is a generic consequence of a gas-rich merger at some time in the Galaxy's evolution. The high-$\alpha$ sequence evolves… Expand

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