Abstract

Invited Talk - Plenary

Tuesday, 10 September 2024, 11:30   (Aula 1&2 / virtual plenum)

Magnetic, heavy metal, or composite: Hot subdwarf stars as the result of binary evolution

Matti Dorsch
Universität Potsdam

Hot subdwarf stars are low-mass stars of spectral type O and B (sdO/B) that have very thin or no hydrogen envelopes. Almost all of these core helium burning stars can only form by binary interaction: common envelope evolution, stable Roche lobe overflow, or stellar mergers. Here I present the most interesting results from my PhD thesis. These include subdwarfs that are highly enriched in heavy elements, among them the most lead-rich star ever identified, as well as the first magnetic hot subdwarfs. Additionally, I describe the largest sample of hot subdwarfs with precise measurements of radius, luminosity, and mass. The prevalence of F/G/K-type companions is also discussed, with a focus on how these observations compare to existing evolutionary models, emphasizing significant discrepancies. Lastly, I will briefly outline upcoming large-scale spectroscopic surveys with 4MOST and the Hubble Space Telescope.