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Stellar ages are an important parameter to study the chemical evolution of the Galaxy. In recent years, several studies have established the existence of a relationship between chemical clocks and stellar ages. The Y/Mg clock is a promising technique, but there are still several open questions, such as its validity for metal-poor stars and differences between the thin and thick disk populations. Our aim is to study the behaviour of the Y/Mg chemical clock with stellar ages and the effect of metallicity and population on this chemical clock for a sample of solar-type disk stars. We have derived the precise stellar atmospheric parameters as well as the elemental abundances of Mg and Y through line-by-line differential spectroscopic analysis for a sample of 48 metal-poor solar-type stars based on high-quality, high-resolution ESO/HARPS spectra. From the high-precision Gaia astrometric data, stellar masses and ages were estimated through isochrone-fitting. A joint analysis of our sample, together with a sample of 185 solar-twins and analogues from our previous works, is performed to calibrate the Y/Mg chemical clock in the Galactic disk for -0. 71 Fe/H < +0. 34. Open clusters and stars with asteroseismic ages have been used to validate our relations. Two different populations could be clearly seen in the Mg/Fe - Fe/H plane - the thick and thin disks. We found a metallicity-dependent, strong anti-correlation between the Y/Mg ratio and stellar ages of our sample. For the first time in the literature, we report similar correlations for the thin and thick disk stars. The Y/Mg relation (s) found here for solar-type stars is compatible with the literature using solar-twins. Our relation provides higher accuracy and precision of 0. 45 and 0. 99 Gyr, respectively, comparable with the best accuracy achieved for the solar-twins till date.
Shejeelammal et al. (Tue,) studied this question.