The Ages of Stars

TL;DR

This review discusses various methods for estimating stellar ages, focusing on low-mass stars, highlighting their applicability, strengths, weaknesses, and future prospects with advancing asteroseismology and models.

Contribution

It provides a comprehensive summary of current stellar age-dating techniques, emphasizing low-mass stars and the potential for improved accuracy with upcoming observational and modeling advances.

Findings

Asteroseismology offers promising prospects for precise stellar ages.

Open clusters help calibrate empirical age indicators.

Current age estimates for nearby stars remain mediocre.

Abstract

The age of an individual star cannot be measured, only estimated through mostly model-dependent or empirical methods, and no single method works well for a broad range of stellar types or for a full range in age. This review presents a summary of the available techniques for age-dating stars and ensembles of stars, their realms of applicability, and their strengths and weaknesses. My emphasis is on low-mass stars because they are present from all epochs of star formation in the Galaxy and because they present both special opportunities and problems. The ages of open clusters are important for understanding the limitations of stellar models and for calibrating empirical age indicators. For individual stars, a hierarchy of quality for the available age-dating methods is described. Although our present ability to determine the ages of even the nearest stars is mediocre, the next few years hold great promise as asteroseismology probes beyond stellar surfaces and starts to provide precise interior properties of stars and as models continue to improve when stressed by better observations.