The Prevalence of the $\alpha$-bimodality: First JWST $\alpha$-abundance Results in M31

Understand

We present initial results from our JWST NIRSpec program to study the $\alpha$-abundances in the M31 disk.

• The Milky Way has two chemically-defined disks, the low-$\alpha$ and high-$\alpha$ disks, which are closely related to the thin and thick disks, respectively.
• The origin of the two populations and the $\alpha$-bimodality between them is not entirely clear, although there are now several models that can reproduce the observed features.
• To help constrain the models and discern the origin, we have undertaken a study of the chemical abundances of the M31 disk using JWST NIRSpec, in order to determine whether stars in M31's disk also show an $\alpha$-abundance bimodality.