On the need of the Light Elements Primary Process (LEPP)

Understand

Extant chemical evolution models underestimate the Galactic production of Sr, Y and Zr as well as the Solar System abundances of s-only isotopes with 90<A<130.

• To solve this problem, an additional (unknown) process has been invoked, the so-called LEPP (Light Element Primary Process).
• In this paper we investigate possible alternative solutions.
• Basing on Full Network Stellar evolutionary calculations, we investigate the effects on the Solar System s-only distribution induced by the inclusion of some commonly ignored physical processes (e.g.