The Initial-Final Mass Relation among White Dwarfs in Wide Binaries

TL;DR

This study derives the initial-final mass relation for white dwarfs in wide binaries by analyzing spectra, ages, and metallicities, revealing a correlation between progenitor metallicity and mass loss, and suggesting mass loss occurs mainly on the red giant branch.

Contribution

First empirical determination of the initial-final mass relation using wide binaries with detailed spectroscopic and age analysis.

Findings

Most white dwarf progenitors have initial masses between 1-2 M$_{\ m \odot}$

Progenitor metallicity correlates with the amount of mass loss

Low mass stars tend to lose mass mainly on the red giant branch

Abstract

We present the initial-final mass relation derived from 10 white dwarfs in wide binaries that consist of a main sequence star and a white dwarf. The temperature and gravity of each white dwarf was measured by fitting theoretical model atmospheres to the observed spectrum using a $\chi^{2}$ fitting algorithm. The cooling time and mass was obtained using theoretical cooling tracks. The total age of each binary was estimated from the chromospheric activity of its main sequence component to an uncertainty of about 0.17 dex in log \textit{t} The difference between the total age and white dwarf cooling time is taken as the main sequence lifetime of each white dwarf. The initial mass of each white dwarf was then determined using stellar evolution tracks with a corresponding metallicity derived from spectra of their main sequence companions, thus yielding the initial-final mass relation. Most of the initial masses of the white dwarf components are between 1 - 2 M$_{\odot}$. Our results suggest a correlation between the metallicity of a white dwarf's progenitor and the amount of post-main-sequence mass loss it experiences - at least among progenitors with masses in the range of 1 - 2 M$_{\odot}$. A comparison of our observations to theoretical models suggests that low mass stars preferentially lose mass on the red giant branch.