Kinematics and Velocity Ellipsoid of the Solar Neighborhood White Dwarfs

TL;DR

This paper analyzes the velocity distribution of nearby white dwarfs to understand their kinematics, comparing different samples and subgroups to reveal how composition and temperature influence their velocity dispersions.

Contribution

It provides a detailed kinematic analysis of white dwarfs within 20 and 25 parsecs, highlighting the effects of chemical composition and temperature on their velocity properties.

Findings

Good agreement between 20 pc and 25 pc samples.

Velocity dispersions vary with chemical composition and temperature.

Solar velocity estimates depend on white dwarf subgroups.

Abstract

To determine the velocity ellipsoid of the solar neighborhood white dwarfs, we use the space velocity components of stars. Two samples of white dwarfs are used, 20 pc and 25 pc samples. Beside the two main samples, the solar velocity and velocity dispersions are calculated for the four subsamples, namely DA, non - DA, hot and cool white dwarfs. Comparison between the results of 20 pc sample and those of 25 pc sample gives good agreement, while the comparison between the other subsamples gives bad agreement. Dependence of the velocity dispersions and solar velocity on the chemical composition and effective temperatures are discussed.