31.05.2017: Astrodebata: The nature of the First Stars

Sreda, 31 Maj 2017


V sredo, 31. maja, bo od 12. uri Astrodebato o naravi prvih zvezd imel dr. Gabriele Cescutti (INAF-Tržaški astronomski observatorij). Predavanje bo v predavalnici F4 na Jadranski 19, Fakulteta za matematiko in fiziko, Univerza v Ljubljani. Vljudno vabljeni!

In the last years our group has found that many chemical anomalies observed in very metal-poor halo stars in the light elements suggest the first stellar generations to have been fast rotators (spinstars). Recently, theoretical computations have found that spinstars can also play a role in the chemical enrichment of neutron capture elements providing a early contribution of s-process. By means of a stochastic chemical evolution model, it is possible to identify the spinstars s-process contribution as the missing component responsible for the spread in the ratio between light (Sr) to heavy (Ba) neutron capture elements. A specific distribution is predicted for the isotopic ratio of Ba in halo stars and this imprint could be the smoking gun of the role played by spinstars in the spread of [Sr/Ba] ratio.  In this context, regarding the still unknown origin of the complementary r-process component, I present new constraints on the rate and time scales of r-process events, based on the recent discovery of the r-process rich stars in the ultra faint galaxy Reticulum 2.