Data: 05.05.2026

Lionel Siess (ULB,BE)

On the formation of barium stars

Streszczenie:
Barium stars are chemically peculiar binary systems whose surface enrichment in s‑process elements results from past mass transfer from an asymptotic giant branch companion, now observed as a white dwarf. Although this evolutionary scenario is well established, the observed orbital properties of barium stars, particularly their periods and eccentricities, remain poorly understood. In this seminar I will describe our modeling attempt to reproduce these orbital characteristics. After a brief introduction to chemically polluted binaries and a discussion of the key physical processes involved in our modeling, I will present recent results obtained with the BINSTAR binary evolution code and explore their implications for the formation of barium stars and related systems.