Despite its importance for our comprehension of stellar and galactic evolution, stellar age is one of the most elusive stellar properties. In fact, we are able to determine stellar age with a good precision only in a few cases. Typical methods to determine this quantity are: the study of the chemical abundance of Lithium, stellar kinematics, stellar pulsations analyzed by
The study of the chemical abundances of stars with different age and position in the Milky Way provide crucial information on the formation and evolution of our Galaxy. In particular, heavy elements (i.e. those with the atomic number Z > 30) are produced by the successive capture of neutrons by lighter elements. This occurs by two processes, the slow s-process
Stars more massive than 9 solar masses are efficient chemical labs, where hydrogen and helium are synthesized into other chemical elements, such as oxygen, carbon, and silicon. When these stars explode as supernovae (type I or “core-collpase” supernovae), these chemical elements are ejected into space, enriching the interstellar medium and being in future available to form new generations of stars.
Massive stars are enormous chemical laboratories where heavy chemical elements are synthesized. For instance, the alpha-elements (O, Mg, Si, Ca, and Ti) are produced by nucleosynthetic processes in the interior of massive stars. Moreover, the lifetime of massive stars is much shorter than that of low mass stars: few million years for the former compared to several billion of years
