The ages of (the oldest) stars

Much progress has been achieved in the age-dating of old stellar systems, and even of individual stars in the field, in the more than sixty years since the evolution of low-mass stars was first correctly described. In this paper, I provide an overview of some of the main methods that have been used in this context, and discuss some of the issues that still affect the determination of accurate ages for the oldest stars.Comment: 10 pages, 1 figure. Invited review, to appear in the proceedings of IAU Symp. 334 ("Rediscovering our Galaxy"), ed. C. Chiappini et al., pp. 11-2

Selected topics in the evolution of low-mass stars

Low-mass stars play a key role in many different areas of astrophysics. In this article, I provide a brief overview of the evolution of low-mass stars, and discuss some of the uncertainties and problems currently affecting low-mass stellar models. Emphasis is placed on the following topics: the solar abundance problem, mass loss on the red giant branch, and the level of helium enrichment associated to the multiple populations that are present in globular clusters.Comment: 10 pages, 5 figures. Invited review, to appear in "Ageing low-mass stars: from red giants to white dwarfs", LIAC40 proceeding