Seminar by Shilpa Bijavara Seshashayana on the topic of Florine in open clusters

Seminar by Shilpa Bijavara Seshashayana from Malmö University on the topic of Florine in open clusters.

Title: Fluorine abundances in Open Clusters

Abstract: The study of open clusters (OCs) allows for the determination of accurate values, as they are expected to have a consistent age, distance, and metallicity. Consequently, they are optimal for elucidating the cosmic genesis of complex elements, such as fluorine (F). The objective of this project is to analyze the abundances of F in 13 OCs (also including eight field stars). This is the most exhaustive and homogeneous database to date, which has been designed to derive cosmic F across the galactic disk using OCs. While the principal objective is to comprehend the distribution of galactic F, the abundances of cerium (Ce) are also derived in order to elucidate the interrelationships between fluorine and s-process elements. In addition to the aforementioned elements, the abundances of magnesium (Mg) are derived in order to facilitate the categorization of the thick and thin disk trends of HIP and KIC stars that are included in the sample. The abundances of F and Ce are compared with metallicities, ages, and galactocentric distances in order to provide valuable insights into these elements. Furthermore, the observational data are compared with galactic chemical evolution (GCE) models in order to gain insight into the origin and evolution of F. The spectra were collected using the high-resolution GIANO-B instrument, which operates at the 3.58-meter Galileo National Telescope (TNG) in the near-infrared wavelength range. The Python version of Spectroscopy Made Easy (PySME) was employed for the analysis of the spectra and derivation of stellar parameters. The H-band region was used to derive stellar parameters. The stellar parameters were obtained by analyzing the OH, CN, and CO molecular lines and headbands in addition to the Fe I lines. The K-band HF lines (2.28, 2.33 μm), three K-band Mg I lines (2.10, 2.11, 2.15 $\mu$m), and H-band Ce II lines (1.66, and 1.71 μm) were used to derive F, Mg, and Ce abundances, respectively. When compared with theoretical models, the observed anomalies suggest that both asymptotic giant branch (AGB) stars and massive stars—including a proportion of fast rotators that are more likely to increase with declining metallicity—are necessary to explain the cosmic origin of F from our study.