Photometric and spectroscopic study of the intermediate-age open cluster NGC 2355

TL;DR

This study combines photometric and spectroscopic data to determine the age, metallicity, and chemical composition of the open cluster NGC 2355, providing insights into Galactic disc evolution.

Contribution

It presents a comprehensive analysis of NGC 2355's properties using combined photometric and spectroscopic methods, including chemical abundance measurements.

Findings

NGC 2355 has slightly sub-solar metallicity ([Fe/H] = -0.06)

Age estimated between 0.8 and 1 Gyr

Located at the Galactic disc boundary affecting chemical evolution studies

Abstract

In this paper we analyse the evolutionary status and properties of the old open cluster NGC 2355, located in the Galactic anticentre direction, as a part of the long term programme BOCCE. NGC 2355 was observed with LBC@LBT using the Bessel $B$, $V$, and $I_c$ filters. The cluster parameters have been obtained using the synthetic colour-magnitude diagram (CMD) method, as done in other papers of this series. Additional spectroscopic observations with FIES@NOT of three giant stars were used to determine the chemical properties of the cluster. Our analysis shows that NGC 2355 has metallicity slightly less than solar, with [Fe/H]$=-0.06$ dex, age between 0.8 and 1 Gyr, reddening $E(B-V)$ in the range 0.14 and 0.19 mag, and distance modulus $(m-M)_0$ of about 11 mag. We also investigated the abundances of O, Na, Al, $\alpha$, iron-peak, and neutron capture elements, showing that NGC 2355 falls within the abundance distribution of similar clusters (same age and metallicity). The Galactocentric distance of NGC~2355 places it at the border between two regimes of metallicity distribution; this makes it an important cluster for the study of the chemical properties and evolution of the disc.