Abstract

AbstractThe shape of the luminosity function of white dwarfs (WDLF) is sensitive to the characteristic cooling time and, therefore, it can be used to test the existence of additional sources or sinks of energy such as those predicted by alternative physical theories. However, because of the degeneracy between the physical properties of white dwarfs and the properties of the Galaxy, the star formation history (SFH) and the IMF, it is almost always possible to explain any anomaly as an artifact introduced by the star formation rate. To circumvent this problem there are at least two possibilities, the analysis of the WDLF in populations with different stories, like disc and halo, and the search of effects not correlated with the SFH. These procedures are illustrated with the case of axions.

Highlights

  • Often non-standard theories predict the existence of particles which existence and properties cannot be tested in the terrestrial laboratories as a consequence of the large energies involved

  • The shape of the luminosity function of white dwarfs (WDLF) is sensitive to the characteristic cooling time and, it can be used to test the existence of additional sources or sinks of energy such as those predicted by alternative physical theories

  • Because of the degeneracy between the physical properties of white dwarfs and the properties of the Galaxy, the star formation history (SFH) and the IMF, it is almost always possible to explain any anomaly as an artifact introduced by the star formation rate

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Summary

Introduction

Often non-standard theories predict the existence of particles which existence and properties cannot be tested in the terrestrial laboratories as a consequence of the large energies involved. Because the evolution of white dwarfs is a relatively simple process of cooling, the basic ingredients necessary to predict their behavior are well identified, and there is a solid observational background to test the theoretical results, these stars have proved to be excellent laboratories for testing new ideas in Physics (Isern & Garcıa-Berro 2008) This procedure has allowed to put bounds on the mass of axions (Raffelt 1986; Isern et al 1992, 2008), on the neutrino magnetic momentum (Blinnikov & Dunina-Barkovskaya 1994), the secular drift of the Newton gravitational constant (Vila 1976; Garcıa-Berro et al 1995), the density of magnetic monopoles (Freese 1984) and WIMPS (Bertone & Fairbairn 2008), as well as constraints on properties of extra dimensions (Malec & Besiada 2001), on dark forces (Dreiner et al 2013), on modified gravity (Saltas et al 2019), and formation of black holes by high energy collisions (Giddings & Mangano 2008).

Energy losses by neutrinos
Influence of the DA non-DA character
The axion case
Variable white dwarfs
The luminosity function
Findings
Discussion and conclusions
Full Text
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