Thesis Topic: Constraining Stellar Interiors and Mixing via Depletion Sequences of Light Elements


Thesis Supervisor: Francesca Primas




Lithium (Li), beryllium (Be) and boron (B), usually referred to as "the light elements", represent a powerful diagnostic for studying stellar interiors and stellar mixing. Because they burn at relatively low, but slightly different (and increasing) temperatures, they are expected to show different degrees of depletion and/or dilution at different times. Lithium, which is destroyed at the lowest temperature of all three elements (2.5×10^6K) is expected to deplete first, followed by Be (~3.5 ×10^6 K) and B (~5×10^6K). The ability to detect all three of them (or at least Li and Be) in the same objects allows one to make detailed comparison between the observations and the predictions of different stellar mixing/interiors models. Due to the location of main abundance indicators of the three light elements, there is a wealth of data for lithium, but significantly less data for Be and even less for B.

This PhD project will focus on building Li and Be depletion sequences, in order to test and constrain a variety of stellar mixing processes by comparing Be to its Li counterparts (some of the latter are already available, either in the literature or in data archives). The project will use both field and globular cluster stars, with the latter being much more challenging observationally but offering a different origin (as a system in its own) with respect to field stars. This work aims at setting the ground for future work, going further out of the Galaxy.

Return to list of thesis topics