Abstract
The histories of the systems Sirius AB, Procyon AB, 40 Eri BC and Stein 2051 AB are examined. It is assumed that the changes in the orbital elements are a direct result of mass loss from `the white dwarf precursor component. This loss is considered to be iso- tropic and no exchange between the components is allowed. These histories, coupled with observed atmospheric abundances, theoretical ages and cooling times lead to the conclusion that stars as massive as 10M⊙ can be dwarf progenitors. Indeed, in the case of Sirius B, there is evidence that the progenitor mass was not less than 8M0 and that the star did not lose mass in an explosive manner.
