Bibcode
                                    
                            Dufton, P. L.; Lennon, D. J.; Villaseñor, J. I.; Howarth, I. D.; Evans, C. J.; de Mink, S. E.; Sana, H.; Taylor, W. D.
    Referencia bibliográfica
                                    Monthly Notices of the Royal Astronomical Society
Fecha de publicación:
    
                        5
            
                        2022
            
  Número de citas
                                    13
                            Número de citas referidas
                                    11
                            Descripción
                                    The evolutionary status of Be-type stars remains unclear, with both single-star and binary pathways having been proposed. Here, VFTS spectroscopy of 73 Be-type stars, in the spectral-type range, B0-B3, is analysed to estimate projected rotational velocities, radial velocities, and stellar parameters. They are found to be rotating faster than the corresponding VFTS B-type sample but simulations imply that their projected rotational velocities are inconsistent with them all rotating at near critical velocities. The de-convolution of the projected rotational velocities estimates leads to a mean rotational velocity estimate of 320-350 km s-1, approximately 100 km s-1 larger than that for the corresponding B-type sample. There is a dearth of targets with rotational velocities less than 0.4 of the critical velocity, with a broad distribution reaching up to critical rotation. Our best estimate for the mean or median of the rotational velocity is 0.68 of the critical velocity. Rapidly rotating B-type stars are more numerous than their Be-type counterparts, whilst the observed frequency of Be-type stars identified as binary systems is significantly lower than that for normal B-type stars, consistent with their respective radial-velocity dispersions. The semi-amplitudes for the Be-type binaries are also smaller. Similar results are found for a Small Magellanic Cloud Be-type sample centred on NGC 346 with no significant differences being found between the two samples. These results are compared with the predictions of single and binary stellar evolutionary models for Be-type stars. Assuming that a single mechanism dominated the production of classical Be-type stars, our comparison would favour a binary evolutionary history.
                            Proyectos relacionados
                 
Propiedades Físicas y Evolución de Estrellas Masivas
            
    Las estrellas masivas son objetos claves para la Astrofísica. Estas estrellas nacen con más de 8 masas solares, lo que las condena a morir como Supernovas. Durante su rápida evolución liberan, a través de fuertes vientos estelares, gran cantidad de material procesado en su núcleo y, en determinadas fases evolutivas, emiten gran cantidad de
            
            Sergio
            
                        Simón Díaz