Chemical-abundance analysis of main-sequence stars in GALAH DR4 and the NASA exoplanet database

Abstract

In this work we analyze the elemental abundances of a selected main-sequence stars data set from the GALAH DR4 survey by means of a dimensionality reduction technique (UMAP) and a clustering method (Agglomerative Clustering with Ward linkage). This will allow us, with some future work, to define robust and interpretable chemical-abundance groups that are more finegrained than the usual thin vs. thick disk dichotomy. Using the subsample of known exoplanet host stars within the GALAH DR4 sample, we explore possible trends of planet occurrence rate with the abundance group, finding little statistical evidence.