Models for highly flattened, rapidly rotating cool stars in a Newtonian approximation

We investigate the physical characteristics of single, rapidly rotating whi te dwarfs, which could form as a result of a merger of two white dwarfs wit h different masses and filled Roche lobes, due to the radiation of gravitat ional waves. When the merging of the binary components occurs without loss of mass and angular momentum, the merger products are subject to secular in stability, and the density in their cores does not exceed similar to 10(8) g/cm(3). Models are constructed for rapidly rotating neutron stars, which c ould form after the collapse of rotating iron cores of evolved massive star s. Dynamically unstable neutron-star models are characterized by a shift of the maximum density from the rotational axis. The total momentum of such n eutron stars is about half the maximum possible momentum for the evolved co res of massive stars. (C) 2001 MAIK "Nauka/Interperiodica".