White dwarfs are the evolutionary end point of the vast majority of stars (97 per cent),where a large fraction of systems, around 25 per cent, are close enough to a binary companion that mass is transferred from one star to the other, changing the structures of both stars and their subsequent evolution. We present the APOGEE-GALEX-Gaia catalog of

White dwarfs are the burnt-out cores of Sun-like stars and are the fate of 97 per cent of the stars in our Galaxy. The internal structure and composition of white dwarfs are hidden by their high gravities, which causes all elements apart from the lightest ones to settle out of their atmospheres. The most direct method of probing the inner structure