Challenges in observational studies of heavy elements, featuring Camilla Hansen (Goethe University Frankfurt)

Hosted by: Linda Lombardo (INAF Trieste)

Abstract: Heavy elements make up the largest part of the periodic table and they still pose a large number of open questions associated with their formation. Most of the heavy elements form via neutron captures that happen on a slow (s-process), intermediate (i-process) or a rapid (r-process) scale (when comparing to the following beta decays).  In this talk I will present a homogeneous follow-up observational study targeting light as well as heavy elements in about 50 metal-poor stars. Our study provides new insights into the formation of the third r-process peak (Ir, Os, Pt) as well as challenges we face when deriving abundances of even heavier elements (Th), such as shortcomings in our models as well as atomic physics. A few peculiar stars stand out in the study by either having a very high or very low level of heavy elements in their atmospheres. I will discuss the possible origin (spatial as well as nuclear formation) of these peculiar stars.