In November 2019, the nearby single, isolated white dwarf LAWD 37 aligned closely with a distant background source and caused a so-called microlensing event. Leveraging astrometry from ESA’s Gaia mission and follow-up data from the NASA/ESA Hubble Space Telescope, astronomer measured the astrometric deflection of the background source and obtain a mass for LAWD 37. This image shows how microlensing was used to measure the mass of the white dwarf...
