Program: GS-2018B-Q-117

We have recently performed a detailed spectroscopic and photometric model atmosphere analysis of 158 white dwarfs for which precise trigonometric parallax measurements are available. 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. We were awarded 14.3 h of Gemini time in 2018A to observe our four spring targets. Here we request 16.1 hours of Gemini time to obtain follow-up high-resolution spectroscopy of the remaining five fall targets to finish our program and constrain the orbital periods and 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.