ARE THE OBSERVED FREQUENCIES OF DOUBLE DEGENERATES AND SN IA CONTRADICTORY

We calculate the expected birthrate and number of double white dwarf systems in the Galaxy. The predicted rate of mergers of white dwarf pairs with a total mass exceeding the Chandrasekhar mass is consistent with the rate of Type la supernovae. We show that the results of surveys which attempted to discover double white dwarf systems are not in conflict with the predictions of binary evolution theory. We identify the orbital period range 2-30 hr as one in which searches for double white dwarf systems are most likely to be successful.