the He core flash, during both the central and shell He-burning phases, allowing us to deduce some interesting differences between models whose Red Giant Branch progenitor has experienced the H-flash and canonical models. In particular, the Asymptotic Giant Branch evolution of extremely metal-deficient stars and the occurrence of thermal pulses are strongly affected by the previous RGB evolution.\
author:
- 'H. Schlattl, S. Cassisi, M. Salaris, A. Weiss\'
title: 'On the helium flash in low-mass Population III Red Giant stars '
---

Introduction
============

The most metal-deficient stars in our Galaxy provide astronomers with a wealth of information about the physical conditions of the universe soon after the Big Bang in the early epoch of galaxy formation. In particular, the first generation of stars — commonly called — which formed from primordial, essentially metal-free matter, should provide the oldest bright objects in galaxies. Therefore, the identification and the analysis of the properties of this class of stars should offer an unique tool for investigating the chemical and physical conditions in the very early history of our universe.

Owing to their importance for several fundamental cosmological questions, several attempts have already been made to find zero-metal and/or extremely metal-poor stars. The 