Local stellar formation history from the 40 pc white dwarf sample

ABSTRACT We derive the local stellar formation history from Gaia-defined 40 pc white dwarf sample. This is currently largest volume-complete sample of dwarfs for which spectroscopy available, allowing classification chemical abundances at photosphere, and subsequently accurate determination atmospheric parameters. create a population synthesis model show that uniform last ≈10.5 Gyr provides satisfactory fit to observed distribution absolute Gaia G magnitudes. To test robustness our derivation, we vary various assumptions in model, including initial mass function, initial-to-final relation, kinematic evolution, binary fraction, cooling time-scales. From these tests, conclude have an insignificant effect on derived relative rate as function look-back time. However, onset (age Galactic disc) sensitive variety input parameters models. Our gives much better magnitudes than most previous studies.