Solar twins in M67 : Evolutionary status and lithium abundance

TL;DR

This study uses lithium evolutionary models to determine the age and mass of solar twin candidates in M67, confirming the cluster's solar-like age and mass, and validating M67 as a solar proxy.

Contribution

The paper provides precise age and mass estimates of solar twins in M67 using lithium models, improving cluster age constraints and confirming its status as a solar analog.

Findings

M67's age is estimated at 3.87 Gyr with uncertainties.

The three solar twins have masses close to the Sun within errors.

M67's age aligns with the Sun's, validating it as a solar proxy.

Abstract

We determine the age and mass of the three best solar twin candidates in open cluster M67 through lithium evolutionary models. We computed a grid of evolutionary models with non-standard mixing at metallicity [Fe/H] = 0.01 with the Toulouse-Geneva evolution code for a range of stellar masses. We estimated the mass and age of 10 solar analogs belonging to the open cluster M67. We made a detailed study of the three solar twins of the sample, YPB637, YPB1194, and YPB1787. We obtained a very accurate estimation of the mass of our solar analogs in M67 by interpolating in the grid of evolutionary models. The three solar twins allowed us to estimate the age of the open cluster, which is 3.87+0.55-0.66 Gyr, which is better constrained than former estimates. Our results show that the 3 solar twin candidates have one solar mass within the errors and that M67 has a solar age within the errors, validating its use as a solar proxy. M67 is an important cluster when searching for solar twins.