Program: GN-2018A-Q-116

We have recently performed a detailed spectroscopic and photometric model atmosphere analysis of 158 white dwarfs for which precise trigonometric parallax measurements are available from the ground-based parallax programs and the Gaia Data Release 1. Based on this analysis, we identify 15 double degenerates in the solar neighborhood, six of which were previously confirmed to be in short period systems. The remaining nine objects are excellent binary candidates as well. Here we request Gemini time to obtain follow-up high-resolution spectroscopy of four spring targets to constrain the orbital periods and component masses of these unique binary systems and to confirm or rule out supernova Ia progenitors. We will use this sample to constrain the double degenerate merger rate in the Solar neighborhood. A comparison with the Type Ia supernovae rate will demonstrate whether the double degenerate channel contributes significantly to SNe Ia or not.