Program: GN-2020A-DD-113

We performed a detailed model atmosphere analysis of more than 50,000 white dwarfs in the Montreal White Dwarf Database with Gaia DR2 parallaxes. We identify 3 objects with masses near the Chandrasekhar mass limit. Here we propose to obtain follow-up spectroscopy of these three objects to confirm their nature, precisely constrain their atmospheric composition, temperatures, and masses. If confirmed, these objects would be the most massive white dwarfs ever found, they would provide an observational constraint on the Chandrasekhar limit, and experimentally constrain the upper limit for stellar cores that escape collapse into neutron stars.