Abundances of Sodium (Na) and Europium (Eu) in bulge field stars

• Grant number: 24/05122-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2024
• End date: December 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Stellar Astrophysics
• Principal Investigator: Beatriz Leonor Silveira Barbuy
• Grantee: Rafael Pereira Nunes
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 20/15245-2 - The multi-object spectrograph (MOSAIC) for the extremely large telescope: spectroscopy of stellar populations in the milky way and external galaxies, AP.ESP

Abstract

Chemical abundances in the Galactic bulge are key to understandthe early enrichment from massive supernovae. In particular in the Galactic bulge, the gas was dense and star formation and explosion of the first supernovae caused a fast chemical enrichment. We have a sample of bulge starsobserved at high-resolution spectroscopy with the Very Large Telescope at the European Southern Observatory. Several papers were already produced using this sample. The earliest paper however used, at the time, a code thatdid not take into account the association of atoms into molecules,and this has caused a probable overabundance of Sodium.In the present work we intend to revise the Sodium (Na) abundance in the samplestars, using an updated and well-tested code.We also intend to recompute Europium (Eu) such as to have less spread in its abundances, and apply a model of chemical evolution. Europium is the reference element for rapid neutron-capture, and its study is important for the understanding of r-element production, intensified in the last years, due to the revelation of nucleosynthesis in kilonovae.