Seminars

Seismology of solar-like stars along their evolution
Martin Farnir (STAR Institute Université de Liège)

Salle de réunion AGO (local -1/14), Institut d'Astrophysique et de Géophysique
Bâtiment B5c, Quartier Agora, Allée du 6 Août, 19C, B-4000 Liège 1 (Sart-Tilman)

The advent of space-borne missions lead to the acquisition of extremely precise data. This allowed us to unveil the secrets harboured by stars with unmatched accuracy. This was thanks to asteroseismology, the science of stellar oscillations and their relation with the stellar structure. In this talk, I will present tools I develop to take full advantage of the information held by stellar oscillations of solar-like stars - i.e. stars with masses similar to our Sun - along their evolution, from the main sequence all the way to the red-giant phase. These are WhoSGlAd, for the study of acoustic glitches - sharp feature in the stellar structure leaving a signature in the oscillation spectrum - EGGMiMoSA, suited to the study of the complex mixed-modes - modes displaying both a pressure and gravity nature - pattern displayed by subgiant and red-giant stars, and PORTE-CLES, a minimisation tool for the search of optimal stellar models, representative of a set of observables.

Orion’s Massive Stars: Delta and Epsilon Ori
Alžběta Oplištilová (STAR Institute Université de Liège)

Salle de réunion AGO (local -1/14), Institut d'Astrophysique et de Géophysique
Bâtiment B5c, Quartier Agora, Allée du 6 Août, 19C, B-4000 Liège 1 (Sart-Tilman)

Massive stars are cosmic engines. By exploding as supernovae, they power galaxies, shape the interstellar medium, and enrich it with heavy elements. Yet, their inner workings remain among the most challenging frontiers in stellar astrophysics. The evolution of massive stars is critically influenced by multiplicity; most have one or more companions, while a few remain single. This raises the question: could these single stars be the end products of multiple systems? Interferometry is one of the best methods for detecting and characterising stellar multiplicity. The Orion complex is the nearest massive-star-forming region with multiple OB stars, and thus the most suitable for detailed studies. It hosts a number of massive stars, particularly in the Orion Belt. I constructed two complex models: the triple star Delta Ori and the single star Epsilon Ori using interferometric data in synergy with astrometry, photometry, high-resolution spectroscopy, and spectral energy distribution. Delta Ori is currently in the pre-mass-transfer evolutionary stage, while Epsilon Ori is a significantly oblate supergiant due to its rapid rotation. As the only massive single star in the Orion Belt, Epsilon Ori likely follows a non-standard evolutionary path.

Genesis: the ESA mission to measure Earth down to the millimeter
Gilles Wautelet (LPAP, STAR Institute, ULiège)

Salle de réunion AGO (local -1/14), Institut d'Astrophysique et de Géophysique
Bâtiment B5c, Quartier Agora, Allée du 6 Août, 19C, B-4000 Liège 1 (Sart-Tilman)

TBD