High-Resolution Infrared Spectroscopy of the Dust-Obscured Metal-Poor Open Cluster Trumpler 5

TL;DR

This study provides a detailed chemical and photometric analysis of the dust-obscured, metal-poor open cluster Trumpler 5 using high-resolution infrared spectroscopy and CMD analysis, revealing its age, reddening, and elemental abundances.

Contribution

Introduces a new method for estimating stellar surface gravity using infrared spectral lines and applies comprehensive spectroscopic and photometric analyses to Trumpler 5.

Findings

Derived chemical abundances for over 20 elements.

Estimated the cluster's age at approximately 2.50 Gyr.

Determined the reddening value as E(B-V)≈0.76.

Abstract

Trumpler 5 is a moderately old, dust-obscured metal-poor open cluster. In this study, high-resolution near-infrared spectroscopic data of seven giant stars from the Trumpler 5 cluster were analyzed to derive chemical abundances for 20 elements and $^{12}C/^{13}C$ ratios. Color-magnitude diagram (CMD) analysis of BV and Gaia photometry has also been performed for a comprehensive study of the cluster. Thanks to the methodology employed, some targets are studied for the first time. Additionally, it provides a detailed color-magnitude diagram analysis using photometric and spectroscopic data. We gathered high-resolution spectra for seven Trumpler 5 red giants in the near-infrared H and K wavelength domains, using the Immersion Grating INfrared Spectrometer (IGRINS). We introduced a method to initially estimate the stellar surface gravity (log g) by using calibrated equivalent widths of the Ti II line at 15873 {\AA} from a large sample. We performed standard spectroscopic analyses to refine the model atmospheric parameters of our targets and determined the chemical abundances primarily through spectrum synthesis. We also performed color-magnitude diagram analyses to extract differential reddening correction to compare cluster parameters both with and without corrections. We derived stellar parameters for seven members of Trumpler 5 with our method and the results are consistent with both the literature and other methods. We also inferred elemental abundances for more than 20 species, along with the $^{12}C/^{13}C$ ratios. The elemental abundances are in good agreement with the literature values for similar targets. Through CMD analysis, we found the reddening value, E(B-V)$\simeq$0.76 and estimated the age of the cluster to be approximately 2.50 Gyr.