Turning it up to 11: accretion outbursts in young stellar objects

le 15 décembre 2023, 10h45 à 12h45, Fernando Cruz, salle Jules Verne, OMP, site Belin

Resumé: Accretion is among the most important physical processes during the formation of stars. Eruptive young stars are young stellar objects (YSOs) that experience sudden and dramatic accretion outbursts, where the mass accretion rate can increase by up to 5 orders of magnitude in a few months. Astronomers have traditionally split these stars into two categories: FUors for stronger and long-lasting events, and EXors for weaker and shorter events. Five decades after their discovery and there are significant questions that remain unanswered: What is the triggering mechanism behind these events? Do all YSOs experience them? What effects do they have on the young stars? On their disks? On the forming planets? On the local star-forming region?
During this seminar I will present the current status of the field, and our steps and missteps towards answering these questions. I will show how the FUor/EXor classification system does not apply for all eruptive young stars, and present a recently proposed system organization structure that focuses on the individual events and not the star. I will present works on the protostellar disks of eruptive young stars and how they separate from other young stars, the possible relationship between accretion variability and jets/outflows, and how the accretion bursts drive changes of the mineralogy and chemistry of the system. Finally, I will explain the search for new accretion bursts and eruptive young stars, and highlight the importance of these events in the global picture of star formation.