Improved Main Sequence Turnoff Ages of Young Open Clusters: Multicolor UBV Techniques & the Challenges of Rotation

Understand

Main sequence turnoff ages in young open clusters are complicated by turnoffs that are sparse, have high binarity fractions, can be affected by differential reddening, and typically include a number of peculiar stars.

• Furthermore, stellar rotation can have a significant effect on a star's photometry and evolutionary timescale.
• In this paper we analyze in 12 nearby open clusters, ranging from ages of 50 Myr to 350 Myr, how broadband UBV color-color relations can be used to identify turnoff stars that are Be stars, blue stragglers, certain types of binaries, or those affected by differential reddening.
• This UBV color-color analysis also directly measures a cluster's E(B-V) and estimates its [Fe/H].