Chemical composition of evolved stars in the open cluster NGC 2506

TL;DR

This study analyzes the chemical abundances of key elements in evolved stars of the open cluster NGC 2506, revealing specific elemental depletions and enhancements that inform stellar evolution and galactic chemical history.

Contribution

It provides detailed chemical abundance measurements for multiple elements in evolved stars of NGC 2506, including isotope ratios, which were not previously reported for this cluster.

Findings

Carbon is depleted by about 0.2 dex compared to the Sun.

Nitrogen is overabundant by about 0.3 dex.

C/N and 12C/13C ratios are significantly lowered.

Abstract

In this study we present abundances of 12^C, 13^C, N, O and up to 26 other chemical elements in two first ascent giants and two core-helium-burning 'clump' stars of the open cluster NGC 2506. Abundances of carbon were derived using the C_2 Swan (0,1) band head at 5635.5 A. The wavelength interval 7940-8130 A, with strong CN features, was analysed in order to determine nitrogen abundances and carbon isotope ratios. The oxygen abundances were determined from the [O I] line at 6300 A. NGC 2506 was found to have a mean [Fe/H]=-0.24 +- 0.05 (standard deviation). Compared with the Sun and other dwarf stars of the Galactic disc, mean abundances in the investigated clump stars suggest that carbon is depleted by about 0.2 dex, nitrogen is overabundant by about 0.3 dex and other chemical elements have abundance ratios close to solar. The C/N and 12^C/13^C ratios are lowered to 1.25 +- 0.27 and 11 +- 3, respectively.