Sarah Martell

The abundance fingerprints of escaped globular cluster stars in GALAH

Light-element abundance anomalies in globular clusters are a classic observational mystery. Whilst roughly half of the stars in each cluster have scaled Solar abundance patterns, the other half are depleted in carbon, oxygen and magnesium and enhanced in nitrogen, sodium and aluminium, and a comprehensive and realistic explanation for this phenomenon has not yet been found. Even if we don’t completely understand globular cluster abundance anomalies, we can make use of them. There are no other environments in the Galaxy where this abundance pattern is common, so it is a relatively unique and reliable chemical tag to identify stars that originally formed in globular clusters and subsequently escaped. The latest GALAH data release includes carbon and nitrogen abundances for the first time, so I am investigating how well the different abundances perform at identifying globular cluster escapees, whether they agree, and what the optimal chemical tag is for these stars in GALAH DR4.