The age of the most nearby star

TL;DR

This study evaluates the precision of stellar age determination using solar models, revealing current limitations and the impact of diffusion processes on age estimates.

Contribution

It demonstrates the effects of diffusion and model assumptions on solar age estimates, highlighting the inherent uncertainties in stellar age determination.

Findings

Neglecting diffusion causes up to 100% deviation from true age.

Including diffusion yields ages about 10% too high.

Current models cannot achieve higher accuracy in stellar age estimation.

Abstract

We address the question how accurately stellar ages can be determined by stellar evolution theory. We select the star with the best observational material available - our Sun. We determine the solar age by fitting solar evolution models to a number of observational quantities including several obtained from helioseismology, such as photospheric helium abundance or p-mode frequencies. Different cases with respect to the number of free parameters and that of the observables to be fitted are investigated. Age is one of the free parameters determined by the procedure. We find that the neglect of hydrogen-helium-diffusion leads to ages deviating by up to 100% from the true, meteoritic solar age. Our best models including diffusion yield ages by about 10% too high. The implication for general stellar age determination is that a higher accuracy than that can not be expected, even with the most up-to-date models. Our results also confirm that diffusion as treated presently in solar models is slightly too effective.