We use a sample of 938 red clump giant stars located in the direction of the Galactic long bar to study the chemistry of Milky Way bar stars .
Kinematically separating stars on bar orbits from stars with inner disk orbits , we find that stars on bar-like orbits are more metal rich with a mean iron abundance of \langle [ { Fe / H } ] \xspace \rangle = +0.30 compared to \langle [ { Fe / H } ] \xspace \rangle = +0.04 for the inner disk .
Spatially selecting bar stars is complicated by a strong vertical metallicity gradient of -1.1 { dex } / { kpc } \xspace , but we find the metallicity distribution varies in a manner consistent with our orbital selection .
Our results have two possible interpretations : Either the most metal rich stars in the inner Galaxy ( i ) preexisted the bar , but were kinematically cold at the time of bar formation and therefore more easily captured onto bar orbits when the bar formed , or ( ii ) formed after the bar , either directly onto bar following orbits , or were captured by the bar after their formation .