Accuracy of Star Cluster Parameters from Integrated UBVRIJHK Photometry

TL;DR

This study assesses how well the UBVRIJHK photometric system can determine star cluster properties like age, metallicity, and extinction, especially when combined with infrared data and accurate measurements.

Contribution

It demonstrates that combining UBVRI with JHK photometry effectively breaks degeneracies, improving parameter estimation accuracy in star cluster analysis.

Findings

Infrared data improves parameter determination accuracy.

Photometry accuracy better than 0.05 mag is crucial.

Combining optical and infrared data reduces degeneracies.

Abstract

We investigate the capability of the UBVRIJHK photometric system to quantify star clusters in terms of age, metallicity and color excess by their integrated photometry in the framework of PEGASE single stellar population (SSP) models. The age-metallicity-extinction degeneracy was analyzed for various parameter combinations, assuming different levels of photometric accuracy. We conclude, that most of the parameter degeneracies, typical to the UBVRI photometric system, are broken in the case when the photometry data are supplemented with at least one infrared magnitude of the JHK passbands, with an accuracy better than ~0.05 mag. The presented analysis with no preassumptions on the distribution of photometric errors of star cluster models, provides estimate of the intrinsic capability of any photometric system to determine star cluster parameters from integrated photometry.