Massive stars are transcendental in many fields of current astrophysical research. They are the most luminous stars, visible even at extreme far distances in the local Universe, and also perceptible at high redshifts in the integrated light of star-forming galaxies. Because of their enormous luminosities, up to few 10^6 solar luminosities, they possess winds with mass-loss rates of 10^-8 to 10^-4 solar masses per year and terminal velocities between 100 to 2500 km/s. They also possess an important influence on the dynamics and energetics of the interstellar medium, which they enrich with nuclear-processed material.  Furthermore, the most energetic processes in the Universe, gamma-ray bursts (GRB), are suspected to result from the final collapse of a massive star to a black hole. A deeper knowledge of the evolution of massive stars is thus a necessity for improving our understanding of the Universe as a whole. Our group is advocating to study the impact of the mass loss (known as wind)  in stellar evolution and how the different physical solutions of the standard radiation-driven wind theory can explain many of the current open problems in describing the circumstellar environment of these objects.

Compact binary

Binary stars with at least one compact component (white dwarf, hot subdwarf star, neutron star, black hole), represent testbeds for studying a wealth of phenomena with implications for several astrophysical areas. Eclipsing systems provide the only model-independent determination of masses and radii. Interacting binaries allow for the investigation of mass transfer, the structure, and physics of (accretion) discs, or the flow along magnetic field lines. Novae enrich the interstellar medium with nuclear-processed material, and their shells serve as geometrical distance indicators. Finally, the study of compact binary evolution involves such diverse topics as the interaction with circumstellar material (common envelope), the response of a main-sequence star to ongoing mass loss, the response of a compact star to ongoing mass accretion, angular momentum evolution driven by magnetic braking and gravitational radiation, and, last but not least, the nature of the progenitors of supernovae of Type Ia, one of the most important elements of the cosmological distance scale. The compact binary group at IFA represents the largest research group in this area in Chile and counts among the most active ones worldwide. While each member pursues his/her individual line of research, there exists a strong synergy that is focused on contributing to our understanding of the evolution of compact binaries.