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arXiv · 2401.09635

Stellar population astrophysics (SPA) with the TNG. Abundance analysis of nearby red giants and red clump stars: combining high resolution spectroscopy and asteroseismology

Nagaraj Vernekar·Sara Lucatello·Angela Bragaglia·Andrea Miglio·Nicoletta Sanna·Gloria Andreuzzi·Antonio Frasca
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Abstract

Context: Asteroseismology, a powerful approach for obtaining internal structure and stellar properties, requires surface temperature and chemical composition information to determine mass and age. High-resolution spectroscopy is a valuable technique for precise stellar parameters (including surface temperature) and chemical composition analysis. Aim: We aim to combine spectroscopic parameters with asteroseismology to test stellar models. Method: Using high-resolution optical and near-IR spectra from GIARPS at the Telescopio Nazionale Galileo, we conducted a detailed spectroscopic analysis of 16 stars photometrically selected to be on the red giant and red clump. Stellar parameters and chemical abundances for light elements (Li, C, N, F), Fe peak, $\alpha$ and n-capture elements were derived using a combination of equivalent widths and spectral synthesis techniques, based on atomic and molecular features. Ages were determined through asteroseismic scaling relations and compared with ages based on chemical clocks, [Y/Mg] and [C/N]. Results: Spectroscopic parameters confirmed the stars as part of the red giant branch and red clump. Two objects, HD 22045 and HD 24680 exhibited relatively high Li abundances, with HD 24680 potentially being a Li-rich giant resulting from mass transfer with an intermediate-mass companion, which already underwent its AGB phase. Stellar parameters derived from scaling different sets of relations were consistent with each other. For what concerns ages, the values based on asteroseismology were in excellent agreement with those derived from theoretical evolutionary tracks, but did not align with ages derived from the chemical clocks [Y/Mg] and [C/N].

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Nagaraj Vernekar, Sara Lucatello, Angela Bragaglia, Andrea Miglio, Nicoletta Sanna, Gloria Andreuzzi, Antonio Frasca. 2024-01-17. Stellar population astrophysics (SPA) with the TNG. Abundance analysis of nearby red giants and red clump stars: combining high resolution spectroscopy and asteroseismology. https://arxiv.org/abs/2401.09635

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