Characterizing the Chemistry of the Milky Way Halo
Ian Roederer (University of Texas)
To what extent does stellar nucleosynthesis trace the hierarchical merger history of the Galaxy, and to what degree is it necessary to know the kinematics of a star in order to correctly interpret its chemical enrichment history? We investigate these questions by performing detailed abundance analyses of stars selected by virtue of their kinematics. We compare the chemistry of the so-called inner and outer components of the halo, finding that the outer halo may be slightly more chemically diverse than the inner halo. We also examine the composition of one of the confirmed building blocks of the halo, a stellar stream, which has the same star-to-star chemical dispersion as field halo stars. These studies are naturally limited by the need to target relatively bright, hence nearby, stars in order to acquire sufficient signal; if we hope to eventually unravel the history of enrichment and accretion of the Galactic halo we must begin to examine samples of stars beyond the Solar neighborhood.
Contact: Ian Thompson
Ian Roederer (University of Texas)
To what extent does stellar nucleosynthesis trace the hierarchical merger history of the Galaxy, and to what degree is it necessary to know the kinematics of a star in order to correctly interpret its chemical enrichment history? We investigate these questions by performing detailed abundance analyses of stars selected by virtue of their kinematics. We compare the chemistry of the so-called inner and outer components of the halo, finding that the outer halo may be slightly more chemically diverse than the inner halo. We also examine the composition of one of the confirmed building blocks of the halo, a stellar stream, which has the same star-to-star chemical dispersion as field halo stars. These studies are naturally limited by the need to target relatively bright, hence nearby, stars in order to acquire sufficient signal; if we hope to eventually unravel the history of enrichment and accretion of the Galactic halo we must begin to examine samples of stars beyond the Solar neighborhood.
Contact: Ian Thompson