Are pre-MS stars older than we thought?
Vol. 5 issue H15, p. 763
Cambridge University Press (CUP) for International Astronomical Union (IAU)
© International Astronomical Union 2010
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.
Special Session 7, IAU XXVII General Assembly
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.