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We theoretically quantify the impact of observational errors on the recoveredage for stars in MS and RGB phases. We adopted Teff, [Fe/H], Delta_nu andnu_max as observational constraints. Artificial stars were sampled from areference isochrone and subjected to random perturbation to simulateobservational errors. Their ages were then recovered by means of a MCMCapproach. The differences between the recovered and true ages were modelledagainst the errors in the observables by means of linear models and projectionpursuit regression models. From linear models we find that no age error sourcedominates. For MS the most important error source is Teff. An offset of 75 Kaccounts for an underestimation of the stellar age from 0.4 to 0.6 Gyr forinitial and terminal MS. An error of 2.5% in nu_max accounted for about -0.3Gyr. A 0.1 dex error in [Fe/H] resulted particularly important only at the endof the MS, with an age error of -0.4 Gyr. For the RGB phase the dominant sourceof uncertainty is nu_max, causing an underestimation of about 0.6 Gyr; theoffset in the effective temperature and Delta_nu caused respectively anunderestimation and overestimation of 0.3 Gyr. We find that the inference fromthe linear model is a good proxy for that from projection pursuit regressionmodels, so that linear models can be safely used thanks to its broadergeneralizability. Finally, we explored the impact on age estimates of addingthe luminosity to the other observational constraints. We assumed - forcomputational reasons - a 2.5% error in luminosity, much lower than the averageerror in the Gaia DR2 catalogue. Even in this optimistic case, the luminositydoes not increase precision of age estimates. Moreover, the luminosity resultedas a major contributor to the variability in the estimated ages, accounting foran error of about -0.3 Gyr in the explored evolutionary phases.

astronomy and astrophysics

Impact of measurement errors on the inferred stellar asteroseismic ages.  Statistical models for intermediate age main sequence and red giant branch  stars