Selected open cluster sample for validating atmospheric parameters: Application to Gaia and other surveys

TL;DR

This study assesses the accuracy of stellar atmospheric parameters from Gaia and ground-based surveys by comparing them with theoretical isochrones of well-selected open clusters, revealing systematic deviations across spectral types.

Contribution

It introduces a benchmark sample of 130 open clusters to evaluate and compare the atmospheric parameters from multiple large spectroscopic surveys against theoretical models.

Findings

Parameter deviations vary across spectral types and surveys.

F, G, K stars show smaller deviations than B, A, M stars.

Temperature dispersion decreases with cooler stars, while gravity dispersion increases.

Abstract

Reliable stellar atmospheric parameters are essential for probing stellar structure and evolution, and for stellar population studies. However, various deviations appear in comparisons with different ground-based spectroscopic surveys. We aim to select high-quality open cluster members and employ the atmospheric parameters provided by the theoretical isochrones of open clusters as a benchmark to assess the quality of stellar atmospheric parameters from Gaia DR3 and other ground-based spectroscopic surveys, such as LAMOST DR11, APOGEE DR17, and GALAH DR4. We selected 130 open clusters with well-defined main sequences within 500 pc of the solar neighborhood as a benchmark sample to estimate the reference atmospheric parameters of the members from the best-fit isochrones of those clusters. By comparing the atmospheric parameters provided by different spectroscopic surveys to the theoretical parameters, we found that the atmospheric parameter deviation and the corresponding dispersions exhibit different variations. The atmospheric parameter deviations of F, G, and K-type stars are smaller than those of B, A, and M-type stars for most surveys. For most samples, the dispersion of Teff decreases as temperature decreases, whereas the dispersion of logg shows the opposite trend.