Stellar population astrophysics (SPA) with the TNG -- The chemical content of the red supergiant population in the Perseus complex

TL;DR

This study analyzes the chemical composition of red supergiant stars in the Perseus complex using high-resolution spectra, revealing detailed elemental abundances and stellar evolutionary signatures consistent with thin disk galaxy chemistry.

Contribution

First detailed chemical abundance analysis of RSGs in Perseus using optical and NIR spectra, providing insights into stellar evolution and Galactic chemical properties.

Findings

Homogeneous half-solar iron abundance with small dispersion

Solar-scaled abundance ratios for iron-peak, alpha, and light elements

Enhanced N and depleted C and $^{12}$C/$^{13}$C ratio indicating stellar mixing processes

Abstract

Context. The Perseus complex in the outer disk of the Galaxy hosts a number of clusters and associations of young stars. Gaia is providing a detailed characterization of their kinematic structure and evolutionary properties. Aims. Within the SPA Large Programme at the TNG, we secured HARPS-N and GIANO-B high-resolution optical and near-infrared (NIR) spectra of the young red supergiant (RSG) stars in the Perseus complex, in order to obtain accurate radial velocities, stellar parameters and detailed chemical abundances. Methods. We used spectral synthesis to best-fit hundreds of atomic and molecular lines in the spectra of the observed 27 RSGs. We obtained accurate estimates of the stellar temperature, gravity, micro and macro turbulence velocities and chemical abundances for 25 different elements. We also measured the $^{12}$C/$^{13}$C abundance ratio. Results. Our combined optical and NIR chemical study provides homogeneous half-solar iron with a small dispersion, about solar-scaled abundance ratios for the iron-peak, alpha and other light elements and a small enhancement of Na, K and neutron-capture elements, consistent with the thin disk chemistry traced by older stellar populations at a similar Galactocentric distance of about 10 kpc. We inferred enhancement of N, depletion of C and of the $^{12}$C/$^{13}$C isotopic abundance ratio, consistent with mixing processes in the stellar interiors during the RSG evolution.