SIMBAD references

Evolutionary models for stars of 1.85, 1.89, 1.97, 2.12, and 2.24 M_☉are calculated, taking all effects of atomic diffusion into account. The stars of 1.97 and 2.24 M_☉are shown to reproduce the position in the H-R diagram of the two components of ο Leonis at an age of 706 Myr. ο Leo A is at T_eff∼6100 K, much cooler than most known Am stars. The abundance anomalies predicted for this star are also in agreement with observations. It is rapidly evolving toward the giant branch but was caught just before mixing wiped out its abundance anomalies. The model is the same as that used by Richer and coworkers for AmFm stars, and no adjustment of parameters was made for the calculations presented here. The anomalies observed on ο Leo are a strong argument in favor of that model for AmFm stars. The earlier model considered for Am stars implied anomalies over a much smaller fraction of the mass of Am stars and appears excluded by the anomalies observed on ο Leo A.