Title Calibration of the [C/N] and [Y/Mg] chemical clocks with asteroseismic ages from the TESS space mission
Authors Pakštienė, Erika ; Tautvaišienė, Gražina ; Bagdonas, Vilius ; Kjeldsen, H ; Winther, M. L ; Drazdauskas, Arnas ; Viscasillas Vazquez, Carlos ; Chorniy, Yiuriy ; Mikolaitis, Šarūnas ; Minkevičiūtė, Renata ; Stonkutė, Edita
DOI 10.1051/0004-6361/202658894
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Is Part of Astronomy & Astrophysics.. Les Ulis : EDP Sciences. 2026, vol. 708, art. no. A250, p. 1-11.. ISSN 0004-6361. eISSN 1432-0746
Keywords [eng] stars: abundances ; stars: evolution ; galaxy: disk
Abstract [eng] Context. Stellar ages are typically very difficult to estimate for field stars. New empirical methods, based on abundance ratios of chemical elements, are emerging and need to be calibrated. Aims. Our main aim is to contribute to revealing relations between [C/N] and [Y/Mg] ratios and stellar ages by determining astro-seismic ages and non-local thermodynamic equilibrium (NLTE) abundances, and accounting for stellar evolutionary stages and birth places in the Galaxy. Methods. We searched for solar pulsations in a sample of 1250 bright F, G, and K giants using data from the TESS space telescope and determined asteroseismic ages using the 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. Results. We determined asteroseismic ages for 218 giants and derived [Y/Mg] and [C/N] relations with age for subsamples of stars in three regions of the Galactic thin disc and the thick disc. Conclusions. The [Y/Mg]-age relation exhibits a clear radial dependence across the Galactic disc, with a steeper trend in the outer disc, progressively flatter relations towards the inner disc, and a very flat trend in the thick disc. NLTE abundances of Mg and especially of Y have to be used in order to obtain a more precise stellar age evaluation from [Y/Mg] ratios. When using [C/N] abundance ratios as stellar age indicators, evolutionary stages of stars have to be taken into account.
Published Les Ulis : EDP Sciences
Type Journal article
Language English
Publication date 2026
CC license CC license description