3 research outputs found
Intermediate mass stars: updated models
A new set of stellar models in the mass range 1.2 to 9 is
presented. The adopted chemical compositions cover the typical galactic values,
namely and . A comparison among
the most recent compilations of similar stellar models is also discussed. The
main conclusion is that the differencies among the various evolutionary results
are still rather large. For example, we found that the H-burning evolutionary
time may differ up to 20 %. An even larger disagreement is found for the
He-burning phase (up to 40-50 %). Since the connection between the various
input physics and the numerical algorithms could amplify or counterbalance the
effect of a single ingredient on the resulting stellar model, the origin of
this discrepancies is not evident. However most of these discrepancies, which
are clearly found in the evolutionary tracks, are reduced on the isochrones. By
means of our updated models we show that the ages inferred by the theory of
stellar evolution is in excellent agreement with those obtained by using other
independent methods applied to the nearby Open Clusters. Finally, the
theoretical initial/final mass relation is revised.Comment: 35 pages, 24 figures, 4 tables, accepted for publication in the
Astrophisycal Journa