StarDance: the non-canonical evolution of stars in clusters
Professor Elena Pancino , University of Florence
Thanks to their ubiquity, brightness, and the fact that they are made of
stars with similar properties, star clusters have been used as astrophysical laboratories or test particles in an impressive range of research domains. However, we still do not understand fundamental details of their formation and evolution. In spite of recent technological progress, a list of unsolved
problems and apparently isolated mysteries has been accumulating over time, some standing since decades. Among them, the existence of multiple stellar populations in globular clusters, with different chemistry, has challenged generations of researchers. They are not the result of classical galactic chemical evolution, mostly mediated by supernovae, and they jeopardize the use of clusters as simple stellar population templates for extragalactic studies. Given the mounting problems faced by the most favored scenarios to explain multiple populations, it is now time to revisit
the foundations of our current thinking. New results show that:
(i) the peculiarities in the chemistry of multiple populations are not limited to the oldest globular clusters; (ii) they can be transient in the evolution of individual cluster stars; and most importantly (iii) binary interactions and fast stellar rotation cannot be neglected in the study of star clusters and do have the capability to produce the observed chemistry. The StarDance hypothesis assumes that multiple stellar populations and five other non-canonical stellar populations (extreme horizontal branch stars and hot sub-dwarfs; extended main sequence turn-offs; red stragglers and sub-subgiants; lithium-rich stars; and blue stragglers) are caused by the
interplay between stellar rotation and binary interactions, that are greatly enhanced in the special environment of star cluster, with spectacular results. Those unable to attend the colloquium in person are invited to participate online through Zoom (Meeting ID: 942 0262 2849, passcode 792771) using the link: https://eu02web.zoom-x.de/j/94202622849?pwd=dGlPQXBiUytzY1M2UE5oUDRhbzNOZz09 During her visit to Heidelberg, Prof. Pancino will be available for meetings by arrangement with her host, Michela Mapelli (mapelli@uni-heidelberg.de).
Heidelberg Joint Astronomical Colloquium
12 Nov 2024, 16:30
Philosophenweg 12, Main Lecture hall (gHS)
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