I am a [PEGASUS]² Marie Skłodowska-Curie fellow at the Center for mathematical Plasma Astrophysics in Leuven (BE) where I study X-ray binaries, systems where a compact object accretes the material from an orbiting companion star. While some X-ray binaries are believed to be progenitors of the gravitational wave sources we have observed since 2015, they also offer a precious testimony of the turbulent twilight of stellar evolution. Along its journey from the Dantean surface of the donor star down to the magnetic vicinity of a neutron star, if not the relativistic surroundings of a black hole, the flow is heated up to several millions degrees and emits copious amounts of X-ray light, which perturbs in return the inflowing material. Observers identified a plethora of behaviors and in particular, a spectacular time variability with bursts, quiescent phases or quasi-periodic oscillations over a broad range of time scales. I use high performance computing codes to investigate how stellar material is captured by compact objects in X-ray binaries. It requires advanced numerical technics and preliminary identification of the dominant physical mechanisms at stake at each scale.
Contrary to the Sun, most stars do not live alone. Using the Wolfram language, I designed didactic mock-ups and interactive applets to illustrate the main phenomena at stake in a close binary system. Give a try to this merry-go-round and sense the unexpected ballistic dynamics in those fascinating environments.
Axisymmetric supersonic flows can be deflected by the gravitational field of a massive body. When the latter is a compact object, the gap between the accretion scale and the actual size of the accretor is so large that few numerical simulations have managed to follow the flow from the shock to the central mass.