Studying the Be Star Content of the Young Open Cluster NGC 1850

• Grant number: 25/04552-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2025
• End date: December 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Stellar Astrophysics
• Principal Investigator: Alex Cavaliéri Carciofi
• Grantee: Luana Alves Antonio
• 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

Recently, our research group at USP developed the first models of young stellar populations fully considering the Be phenomenon, in which a percentage of B-type stars in the population are rapid rotators and form circumstellar disks composed of matter expelled by the stars themselves. These new models, along with machine learning techniques, were applied to analyze data from the young cluster NGC 330, allowing us to study the incidence of Be stars across different spectral subtypes. Among the most important results, the discovery that nearly 80% of B1 spectral subtype stars (with a mass on the order of 13 solar masses) are Be stars stands out, and this fraction decreases for both larger and smaller masses. The main advantage of our method is overcoming known observational biases, such as the fact that Be stars do not always have disks, leading traditional methods to typically underestimate the quantity of such stars in a given population. The central objective of this project is to apply the method to the NGC 1850 cluster and compare its results with the literature. This project is relevant as it represents the second application of the new method and has the potential to result in a specific publication. It is expected that, through this research, the student will develop skills to systematically analyze other open clusters in future studies, contributing to the process of detecting Be stars in observations, as well as clarifying the mechanisms of formation and evolution of these objects.