White dwarfs in Gaia

The ESA Gaia mission has completely revolutionised the field of white dwarfs, increasing the number of known degenerate stars by an order of magnitude (to around 350,000). More specifically, Gaia has precisely measured the parallaxes for billions of stars within our Galaxy, allowing their distances to be inferred. Before Gaia, a faint blue source could have been a nearby faint star like a white dwarf, or a more distant main sequence star, with expensive spectroscopy the only way to distinguish between them. Gaia has therefore allowed white dwarfs to be identified from their absolute brightnesses (corrected for distance).

This has led to several major results in the white dwarf field, including population studies, the identification of white dwarfs that do not cool due to distillation of Ne-22 during the crystallisation phase, and the discovery of hyperrunaway white dwarfs with the fastest velocities of any stars within our Galaxy.