Abstract
Galactic chemical evolution (GCE) describes the changing composition of the Milky Way as a function of space and time, and stars are important drivers of this process by enriching the Galaxy in the elements. Stars are also excellent tracers of GCE, with a star’s composition generally representing the Milky Way’s gas phase composition at the time and location of its birth. In this talk, I will discuss some of my recent work probing CE in the Milky Way’s disk with particular focus on the relative complexity of this process. Recent work has found that the Milky Way disk appears to be relatively chemically simple. For example, with a star’s [Fe/H] abundance and age, one can predict its light, alpha, and iron-peak elements to within 0.02 dex. Furthermore, the chemical “doppelganger rate,” or the rate at which random pairs of field stars are chemically indistinguishable, is high and does not support a scenario where groups of stars born together have unique chemical compositions. I will discuss two ongoing projects investigating the role of the s-process elements in the CE of the disk. My first project investigates the effect of s-process elements on the doppelganger rate of the disk. My second ongoing project identifies and characterizes barium-enhanced stars in our disk. Our preliminary results suggest that the s-process elements play a significant role in enhancing the chemical complexity of the disk, as is also suggested by recent simulations and observations.
