High-resolution spectroscopic study of dwarf stars in the northern sky: Na to Zn abundances in two fields with radii of 20 degrees

TL;DR

This study provides high-resolution spectroscopic analysis of bright dwarf stars near the northern celestial pole, deriving their atmospheric parameters, chemical abundances, and kinematic properties to inform Galactic evolution models.

Contribution

It offers new detailed chemical and kinematic data for 109 stars, focusing on elements from Na to Zn, and compares these with Galactic chemical evolution models, especially in the context of thin and thick disc stars.

Findings

Identified chemical abundance patterns for 23 elements in 249 stars.

Explored [El/FeI] gradients with Galactocentric distance and height.

Compared observed abundances with Galactic chemical evolution models.

Abstract

New space missions, such as NASA TESS or ESA PLATO, will focus on bright stars, which have been largely ignored by modern large surveys, especially in the northern sky. Spectroscopic information is of paramount importance in characterising the stars and analysing planets possibly orbiting them, and in studying the Galactic disc evolution. The aim of this work was to analyse all bright (V < 8 mag) F, G, and K dwarf stars using high-resolution spectra in the selected sky fields near the northern celestial pole. The observations were carried out with the 1.65 m diameter telescope at the Mol\.{e}tai Astronomical Observatory and a fibre-fed high-resolution spectrograph covering a full visible wavelength range (400-850 nm). The atmospheric parameters were derived using the classical equivalent width approach while the individual chemical element abundances were determined from spectral synthesis. For both tasks the one-dimensional plane-parallel LTE MARCS stellar model atmospheres were applied. Results. We determined the main atmospheric parameters, kinematic properties, orbital parameters, and stellar ages for 109 newly observed stars and chemical abundances of 23 chemical species for 249 F, G, and K dwarf stars observed in the present study and in our previous study. The [MgI/FeI] ratio was adopted to define the thin-disc ($\alpha$-poor) and thick-disc ($\alpha$-rich) stars in our sample. We explored the behaviour of 21 chemical species in the [El/FeI] versus [FeI/H] and [El/FeI] versus age planes, and compared the results with the latest Galactic chemical evolution models. We also explored [El/FeI] gradients according to the mean Galactocentric distances and maximum height above the Galactic plane.