u biblioteci Astronomske opservatorije bice odrzan Naucno-strucni skup u sredu 15. decembra sa pocetkom u 13 h. Predavanje ce biti snimljeno i postavljeno na zvanicni YouTube kanal Astronomske opservatorije u Beogradu (https://www.youtube.com/AstronomskaOpservatorijaBeograd).
Izlagac: László Molnár, Konkoly Observatory, ELKH CSFK, Budapest
Naslov predavanja: Hiccuping and barfing red giants, and how to model them
Apstrakt: Red giant and supergiant stars have many processes going on in them, from shell burning and thermal pulses to stellar pulsation an dust creation that can be difficult to interpret and model correctly. Here I present two cases where we used the MESA and GYRE software packages to model the behavior and evolutionary states of such stars. The first, T UMi used to be a Mira star whose pulsation period started to shorten drastically in the last few decades. We reproduced this behavior in the models and matched the observed characteristics, confirming that the star started a thermal pulse (He-shell flash) a few decades ago. We also predict that it might reach minimum radius and period within our lifetimes. The other star we studied is the red supergiant Betelgeuse, which recently went through an unusually faint phase. Not only did we identify a new pulsation mode in the star, we were also able to revise the physical size of the star through the models. Since Betelgeuse is close enough and large enough, its angular diameter can be measured: with that in hand we were able to calculate a new distance to the star based on seismic inferences alone, independent of previous measurements.