Spectroscopic Analysis of B and Be Stars in NGC 3766
Simone Daflon, Marcos Felipe Silva Soares, Wilton Santos, João Victor Sales Silva,Abstract
This study focuses on the young open cluster NGC 3766, known for its split main sequence (MS) and high fraction of Be stars. Using high-resolution spectra from the FLAMES/GIRAFFE spectrograph on the VLT as part of the Gaia-ESO Survey, a sample of 40 B and Be stars was analyzed. Key parameters, including rotational velocities ( V sin i ), effective temperature ( T eff ), surface gravity (log g ), and chemical abundances, were derived using non-LTE models and synthetic spectra. Results show that the cluster stars are chemically homogeneous with solar-like abundances for Silicon, Carbon, Nitrogen, and Oxygen, and exhibit a wide range of rotational velocities (5-322 km s −1 ). The study highlights the influence of stellar rotation on spectral line broadening and discusses the potential role of rotation in the cluster’s MS split and Be/B ratio, paving the way for future investigations.