The Gaia mission has transformed our understanding of open clusters by significantly reducing scatter in colour-magnitude diagrams (CMDs). This improvement allows for more precise stellar modelling, making M67 an ideal test case.

Using Gaia’s refined CMD, we developed new stellar models that avoid common simplifications in 1D modelling, such as mass-independent core overshooting and a constant mixing length parameter. This approach led to an isochrone tailored specifically for M67, now available for download.

We adjusted input physics to match the observed CMD sequence and tested the model-predicted masses against an eclipsing binary at the cluster’s main sequence turnoff.

A χ²-based isochrone fit using our preferred physics yields a cluster age of 3.95 ± 0.16 Gyr.

Read the full study here

📥 Download the M67 isochrone here.