Merging of Components in Close Binaries: Type Ia Supernovae, Massive
  White Dwarfs, and Ap stars
  The "Scenario Machine" (a computer code designed for studies of the evolution
of close binaries) was used to carry out a population synthesis for a wide
range of merging astrophysical objects: main-sequence stars with main-sequence
stars; white dwarfs with white dwarfs, neutron stars, and black holes; neutron
stars with neutron stars and black holes; and black holes with black holes.We
calculate the rates of such events, and plot the mass distributions for merging
white dwarfs and main-sequence stars. It is shown that Type Ia supernovae can
be used as standard candles only after approximately one billion years of
evolution of galaxies. In the course of this evolution, the average energy of
Type Ia supernovae should decrease by roughly 10%; the maximum and minimum
energies of Type Ia supernovae may differ by no less than by a factor of 1.5.
This circumstance should be taken into account in estimations of parameters of
acceleration of the Universe. According to theoretical estimates, the most
massive - as a rule, magnetic - white dwarfs probably originate from mergers of
white dwarfs of lower mass. At least some magnetic Ap and Bp stars may form in
mergers of low-mass main sequence stars (<1.5 mass of the Sun) with convective
envelopes.
