# Evolutionary sequences for hydrogen-deficient white dwarfs

## TL;DR

This paper provides comprehensive evolutionary models for hydrogen-deficient white dwarfs, incorporating detailed physics and atmospheres, enabling improved age and mass estimations for these stars.

## Contribution

It introduces a new set of evolutionary sequences that include non-gray atmosphere models and detailed physics, enhancing previous white dwarf cooling models.

## Key findings

- Extended cooling sequences down to 2,500 K
- Improved accuracy for age and mass determinations
- Inclusion of detailed energy sources and diffusion processes

## Abstract

We present a set of full evolutionary sequences for white dwarfs with hydrogen-deficient atmospheres. We take into account the evolutionary history of the progenitor stars, all the relevant energy sources involved in the cooling, element diffusion in the very outer layers, and outer boundary conditions provided by new and detailed non-gray white dwarf model atmospheres for pure helium composition. These model atmospheres are based on the most up-to-date physical inputs. Our calculations extend down to very low effective temperatures, of $\sim 2\,500$~K, provide a homogeneous set of evolutionary cooling tracks that are appropriate for mass and age determinations of old hydrogen-deficient white dwarfs, and represent a clear improvement over previous efforts, which were computed using gray atmospheres.