Extended Data Fig. 3: Metallicity sensitivity of plateau features.

All solid lines correspond to [Fe/H] = 0 tracks of masses as annotated. The dashed and dotted lines correspond to metallicity variations of the central track, of mass 1.4 M_⊙, or 1.0 M_⊙, as per the legend. The figures illustrate that translating a typical [Fe/H] uncertainty, estimated at 0.05 to 0.10 dex^47,48, into the plateau indicates that for solar-metallicity tracks at 1.40 M_⊙, this uncertainty corresponds to less than 0.02 M_⊙. For solar-metallicity tracks at 1.00 M_⊙, the [Fe/H] uncertainty translates to less than a 0.01 M_⊙ uncertainty. Typical Kepler error bars for small separations of 2 μHz and 3 μHz are shown next to the 1.4 M_⊙ and 1.0 M_⊙ tracks, respectively (see Methods).