My research focuses on the spectroscopic study of massive stars in their various stages of evolution (e.g., O-type, Luminous Blue Variables, Wolf-Rayets). Areas of particular interest are the effect of metallicity on the physical properties of these stars and their stellar winds, and stars in their most advanced evolutionary stages.
Low-metallicity massive stars
Massive stars have played an important role in the evolution of the Universe throughout cosmic history. In the early Universe, heavy elements had not yet formed, and understanding the evolution of metal-poor massive stars is crucial for our understanding of this era. While individual stars can not be studied at the high redshifts corresponding to this age, nearby low-metallicity galaxies provide environments with conditions similar to those at cosmic dawn. The massive stars in these galaxies provide the means to study their evolution at low metallicities.
Image: Low-metallicity galaxy IC1613. Credit: VST/Omegacam Local Group Survey
With their strong, optically thick stellar winds, classical Wolf-Rayet stars represent the late stages of evolution of some of the massive stars. Studying their properties allows for a rare glimpse in the direct pre-supernova evolution of massive stars.
Image: WR124. Credit: NASA, ESA, Judy Schmidt
One of the most striking features of massive stars is their high degree of multiplicity. They are formed almost exclusively is multiple systems, and the majority of them will interact (through, e.g., mass transfer or mergers) during their lifetime. Studying the properties of multiple systems is therefore crucial in understanding massive star evolution.
Image: The massive over-contact binary VFTS 352. Credit: ESO/L. Calçada