Further Investigation of Using RR Lyrae Periods as a Tracer of Multiple Populations in Globular Clusters

Brigham Young University Engineering Building, Provo, UT

Recent work (Racker & Barnes 2024) using Gaia spacecraft data appeared to show a weak but noticeable correlation between the spread of periods for both the ab- and c-type RR Lyrae variable stars in certain Milky Way Globular Clusters (GCs) and the fraction of first-generation to the total number of stars as determined in (Milone et al. 2017). This research further suggests that the correlation is unaffected by angular distance from the GC center relieving the question of whether crowding or other effects impact the results. Then, looking outward, this correlation was used on just over one thousand RR Lyrae stars located within 39 GCs from OGLE survey data of the Large and Small Magellanic Clouds and the Milky Way Bulge to explore the previous relation. The LMC and the Bulge appear to have similar population types as the Milky Way although the LMC seems to have more uniform percentages of first-generation stars.