The Future Evolution of White Dwarf Stars Through Baryon Decay and Time Varying Gravitational Constant

TL;DR

This paper explores how white dwarf stars evolve over cosmic timescales considering potential variations in fundamental constants like the gravitational constant and proton decay, providing insights into the universe's distant future.

Contribution

It introduces a model for white dwarf evolution incorporating time-varying gravitational constant and proton decay, linking stellar evolution to fundamental physics.

Findings

White dwarfs eventually become optically thin due to proton decay effects.

The evolution depends on the variation rate of the gravitational constant.

Proton decay significantly influences the long-term fate of white dwarfs.

Abstract

Motivated by the possibility that the fundamental ``constants'' of nature could vary with time, this paper considers the long term evolution of white dwarf stars under the combined action of proton decay and variations in the gravitational constant. White dwarfs are thus used as a theoretical laboratory to study the effects of possible time variations, especially their implications for the future history of the universe. More specifically, we consider the gravitational constant $G$ to vary according to the parametric relation $G = G_0 (1 + t/t_\ast)^{-p}$, where the time scale $t_\ast$ is the same order as the proton lifetime. We then study the long term fate and evolution of white dwarf stars. This treatment begins when proton decay dominates the stellar luminosity, and ends when the star becomes optically thin to its internal radiation.