Contributions to the Galactic halo from in-situ, kicked-out, and accreted stars

Allyson A. Sheffield, Kathryn V. Johnston, Katia Cunha, Verne V. Smith, Steven R. Majewski

Research output: Contribution to journalArticlepeer-review


We report chemical abundances for a sample of 66 M giants with high S/N high-resolution spectroscopy in the inner halo of the Milky Way. The program giant stars have radial velocities that vary significantly from those expected for stars moving on uniform circular orbits in the Galactic disk. Thus, based on kinematics, we expect a sample dominated by halo stars. Abundances are derived for α-elements and neutron capture elements. By analyzing the multi-dimensional abundance space, the formation site of the halo giants-in-situ or accreted-can be assessed. Of particular interest are a class of stars that form in-situ, deep in the Milky Way's gravitational potential well, but are kicked out of the disk into the halo due to a perturbation event. We find: (1) our sample is dominated by accreted stars and (2) tentative evidence of a small kicked-out population in our Milky Way halo sample.

Original languageEnglish (US)
Pages (from-to)241-246
Number of pages6
JournalProceedings of the International Astronomical Union
Issue numberS317
StatePublished - Aug 1 2015
Externally publishedYes


  • Galaxy: halo
  • Galaxy: structure
  • stars: abundances

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Astronomy and Astrophysics
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health
  • Space and Planetary Science


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