2008/06/30 by J. Isern, E. Garcia-Berro, E. Garcı́a–Berro +4 · 8 citations
Physics and Astronomy · #Astronomy #Astrophysics #Axion #Black dwarf #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark matter #Galaxies: Formation, Evolution, Phenomena #Galaxy #Luminosity #Luminosity function #Particle physics #Physics #Stars #White dwarf #astro-ph
paper · pdf · doi:10.1086/591042
published as Astrophys.J.L. 682 (2008) L109 · 4 pages, 4 figures, replaced with version accepted by The Astrophysical Journal Letters
openalex publication_date 2008/07/09 · arxiv created 2009/01/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
White dwarfs are the end product of the lives of intermediate- and low-mass stars and their evolution is described as a simple cooling process. Recently, it has been possible to determine with an unprecedented precision their luminosity function, that is, the number of stars per unit volume and luminosity interval. We show here that the shape of the bright branch of this function is only sensitive to the averaged cooling rate of white dwarfs and we propose to use this property to check the possible existence of axions, a proposed but not yet detected weakly interacting particle. Our results indicate that the inclusion of the emission of axions in the evolutionary models of white dwarfs noticeably improves the agreement between the theoretical calculations and the observational white dwarf luminosity function. The best fit is obtained for m a cos 2 β meV, where m a is the mass of the axion and cos 2 β is a free parameter. We also show that values larger than 10 meV are clearly excluded. The existing theoretical and observational uncertainties do not yet allow the confirmation of the existence of axions, but our results clearly show that if their mass is of the order of a few meV, the white dwarf luminosity function is sensitive enough to detect their existence.