The recent era of large, ground-based abundance surveys has unraveled the chemical structures of our Milky Way galaxy. The most striking abundance feature is the alpha-abundance bimodality. The low-alpha stars are younger (1-8 Gyr) while the high-alpha stars are older (8-12 Gyr) and have a thicker distribution. There are a number of different

We report on an ongoing search for biomarkers in the potentially habitable atmospheres of a sample of a dozen Y dwarfs with Teff estimated at around or below 400 K. This work is being carried out using public data from large area optical surveys such as DES and PANStarrs. We focus on a search for g-band emission as an analogue to terrestrial

In order to understand stellar evolution, it is crucial to efficiently determine stellar surface rotation periods. Indeed, while they are of great importance in stellar models, angular momentum transport processes inside stars are still poorly understood today. Surface rotation, which is linked to the age of the star, is one of the constraints

JWST will be the most sensitive tool ever built for studying the accretion onto supermassive black holes (SMBHs) at the centers of galaxies. While quasars and bright active galactic nuclei (AGN) provide spectacular examples of this accretion, a vast majority of galaxies have black holes accreting at much lower rates. Although these low luminosity

Context. Our knowledge of the dynamics of stars has undergone a revolution through the simultaneous large amount of high-quality photometric observations collected by space-based asteroseismology and ground-based high-precision spectropolarimetry. They allowed us to probe the internal rotation of stars and their surface magnetism in the whole

Context. Hydrodynamical (or 3D) and non-local thermodynamic equilibrium (NLTE) effects are known to affect abundance analyses. However, there are very few observational abundance tests of 3D and NLTE models. Aims: We developed a new way of testing the abundance predictions of 3D and NLTE models, taking advantage of large spectroscopic survey data