Properties of white dwarfs in a semi-analytic Milky Way model based on Gaia DR3

Abstract

The Just-Jahreiß (JJ) model is a semi-analytic chemo-dynamic model of the Milky Way (MW) Galactic disk (Just & Jahreiß 2010) and is a flexible tool for stellar population synthesis. It is based on an iterative solving approach of the Poisson-Boltzmann equation and reconstructs a self-consistent pair of the total vertical gravitational potential and density. This work deals with extending the JJ model to the WD locus. Currently, we use the initial-final mass relation by Cummings et al. (2018) to bridge the main sequence stellar evolution to WDs. We use solar metallicity BaSTI (Salaris et al. 2022) carbon-oxygen WD isochrones for H atmosphere (type DA) to further evolve a given population in the JJ model. To test the JJ model’s predictions, we use the CNS5 catalogue, a volume-limited sample of stars within 25 pc and the Fusilio et. al 2021 WD catalogue within a volume of 60 pc. We use the default JJ model parameters, this includes two star formation bursts which happened 0.5 Gyrs and 3 Gyrs ago and a IMF as defined in Sysoliatina & Just 2021. The model predicts 11 % more WDs than the data. Most of these are located near or fainter than 15 MG and suggests that the earlier SFR must be adapted or the IMF be re-calibrated. The model also predicts vertical density profile, W velocity profile, age and mass distributions of WDs. Currently, the model predicts a DA mass distribution peak at 0.61 M⊙. The next planned step is to calibrate the SFR based on old WDs in the solar neighbourhood and revisit these properties.