LSST: a New Window into the Be Phenomenon

• Grant number: 23/05083-3
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2025
• End date: January 31, 2028
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Stellar Astrophysics
• Principal Investigator: Alex Cavaliéri Carciofi
• Grantee: Alex Cavaliéri Carciofi
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 18/04055-8 - High precision spectroscopy: from the first stars to planets, AP.TEM

Abstract

The evolution of stars are shaped not only by their masses, but also by their metallicity. The chemical composition of a star will affect its formation, structure and evolution in complex ways, not fully understood yet. However, intriguing evidence propose that the emergence of fast-rotating stars is connected to low-metallicity environments. This project seeks to explore the correlation between metallicity and rotation in massive stars.Be stars are probably the best laboratory to study this connection, as they form a distinct populations of B stars that rotate very fast (fastest among non-degenerate stars). With LSST, we aim at identifying and studying the Be population in the Milk Way. The deep LSST survey, as well its high cadence and expected long term monitoring will allow us to identify Be stars by means of their photometric and color variability, as they form and lose their disks.Our first goal is to develop machine learning or artificial intelligence tools to hunt for Be stars in the LSST data automatically. Once these stars are found, we will use recently developed procedures in our group to study and quantify the disk life cycles. Finally, by comparing the stellar position in the Galaxy with metallicity maps, we can gain insight how this parameter influences the Be phenomenon.A further objective of this project is to establish a comprehensive database of isolated disk events, wherein the star did not possess any previous disk prior to the current event. These events will be thoroughly examined through a combination of observational methods such as spectroscopic campaigns, and theoretical modeling. Our aim is to utilize cutting-edge hydrodynamic simulations to elucidate the enigmatic mechanism of mass loss in Be stars. (AU)