White Dwarf Kinematics vs Mass

TL;DR

This study examines how the movement patterns of young white dwarfs relate to their mass, revealing that more massive white dwarfs move less randomly and are more concentrated near the galactic plane, mainly forming from single star evolution.

Contribution

It provides the first detailed analysis linking white dwarf kinematics with mass, supporting the dominance of single star evolution in high-mass white dwarf formation.

Findings

Dispersion decreases with increasing white dwarf mass

High-mass white dwarfs have reduced scale height

Kinematics of >0.95Msun white dwarfs align with single star evolution

Abstract

We have investigated the relationship between the kinematics and mass of young (<3x10^8 years) white dwarfs using proper motions. Our sample is taken from the colour selected catalogues of SDSS (Eisenstein et al. 2006) and the Palomar-Green Survey (Liebert, Bergeron & Holberg 2005), both of which have spectroscopic temperature and gravity determinations. We find that the dispersion decreases with increasing white dwarf mass. This can be explained as a result of less scattering by objects in the Galactic disk during the shorter lifetime of their more massive progenitors. A direct result of this is that white dwarfs with high mass have a reduced scale height, and hence their local density is enhanced over their less massive counterparts. In addition, we have investigated whether the kinematics of the highest mass white dwarfs (>0.95Msun) are consistent with the expected relative contributions of single star evolution and mergers. We find that the kinematics are consistent with the majority of high-mass white dwarfs being formed through single star evolution.