We present a consistent age ordering for young clusters and groups determined using the contraction of stars through their pre-main-sequence phase. We compare these with ages derived from the evolution of the upper main-sequence stars, and find the upper MS ages are older by a factor 1.5 to 2. We show that increasing the binary fraction and number of equal-mass binaries amongst the O-stars compared to the rest of the MS cannot remove this discrepancy.
@article{arxiv.0909.5320,
title = {Are pre-MS stars older than we thought?},
author = {Tim Naylor and N. J. Mayne},
journal= {arXiv preprint arXiv:0909.5320},
year = {2015}
}
Comments
1 page. Special Session 7, IAU XXVII General Assembly