A new moderately r -process-enhanced metal-poor star , RAVE J093730.5 - 062655 , has been identified in the Milky Way halo as part of an ongoing survey by the R -Process Alliance .
The temperature and surface gravity indicate that J0937 - 0626 is likely a horizontal branch star .
At [ Fe / H ] = -1.86 , J0937 - 0626 is found to have subsolar [ X/Fe ] ratios for nearly every light , \alpha , and Fe-peak element .
The low [ \alpha / Fe ] ratios can be explained by an \sim 0.6 dex excess of Fe ; J0937 - 0626 is therefore similar to the subclass of “ iron-enhanced ” metal-poor stars .
A comparison with Milky Way field stars at [ Fe / H ] = -2.5 suggests that J0937 - 0626 was enriched in material from an event , possibly a Type Ia supernova , that created a significant amount of Cr , Mn , Fe , and Ni and smaller amounts of Ca , Sc , Ti , and Zn .
The r -process enhancement of J0937 - 0626 is likely due to a separate event , which suggests that its birth environment was highly enriched in r -process elements .
The kinematics of J0937 - 0626 , based on Gaia DR2 data , indicate a retrograde orbit in the Milky Way halo ; J0937 - 0626 was therefore likely accreted from a dwarf galaxy that had significant r -process enrichment .