[C/N] and [Y/Mg] chemical clocks

New empirical methods, based on abundance ratios of chemical elements, are emerging and need to be calibrated. Our main aim is to contribute to revealing relations between [C/N] and [Y/Mg] ratios and stellar ages by determining astroseismic ages, non-local thermodynamic equilibrium abundances, and accounting for stellar evolutionary stages and birth-places in the Galaxy.

We searched for solar-type pulsations in a sample of 1250 bright F, G, and K giants using data from the TESS space telescope and determined asteroseismic ages using BASTA and PARAM codes. For the [Y/Mg] relations with age, we determined abundances accounting for deviations from the local thermodynamic equilibrium. For the [C/N] relations with age, we separated stars according to their evolutionary stages.