• stars: early-type;
  • stars: evolution;
  • stars: formation;
  • Hertzsprung–Russell and colour-magnitude diagrams;
  • stars: pre-main-sequence


A new Monte Carlo method has been developed in order to derive ages of young embedded clusters in massive star-forming regions where there is strong differential reddening. After foreground and infrared excess source candidates are removed, each cluster candidate star is individually dereddened. Simulated clusters are constructed using isochrones, an initial mass function, realistic photometric errors, simulated background field populations and extinction distributions. These synthetic clusters are then dereddened in the same way as the real data, obtained from a deep near-infrared survey, and used to derive the ages of three embedded clusters. Results were found to be consistent with those determined using spectrophotometric methods. This new method provides way to determine the ages of embedded clusters when only photometric data are available and there is strong differential reddening.