SCYON Abstract

Received on December 5 2000

Stellar models and Hyades: the Hipparcos test

AuthorsV. Castellani1, S. Degl'Innocenti1, P. G. Prada Moroni2
Affiliation 1 Dipartimento di Fisica, Università di Pisa, and INFN, Sezione di Pisa, Pisa, Italy ,
2 Dipartimento di Fisica, Università di Genova, and INFN, Sezione di Genova, Genova, Italy
Accepted by Montly Notices of the Royal Astronomical Society


We compare theoretical stellar models for Main Sequence (MS) stars with the Hipparcos database for the Hyades cluster to give a warning against the uncritical use of available theoretical scenarios and to show how formal MS fittings can be fortuitous if not fictitious. Moreover, we find that none of the current theoretical scenarios appears able to account for an observed mismatch between theoretical predictions and observations of the coolest Hyades MS stars. Finally, we show that current theoretical models probably give too faint He burning luminosities unlike the case of less massive He burning models, with degenerate progenitors, which have been suggested to suffer the opposite discrepancy.