2008/12/16 by J. Isern, J Isern, S Catalán +5
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #astro-ph #hep-ph
paper · pdf · doi:10.1088/1742-6596/172/1/012005
published as J.Phys.Conf.Ser.172:012005,2009 · 8 pages, 7 figures, to appear in Journal of Physics Conference Proceedings for the 16th European White Dwarf Workshop
arxiv created 2008/12/16 · openalex publication_date 2009/06/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
The evolution of white dwarfs can be 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. Since the shape of the bright branch of this function is only sensitive to the average cooling rate, we use this property to check the possible existence of axions, a proposed but not yet detected weakly interacting particle. We show here that the inclusion of the axion emissivity in the evolutionary models of white dwarfs noticeably improves the agreement between the theoretical calculations and the observational white dwarf luminosity function, thus providing the first positive indication that axions could exist. Our results indicate that the best fit is obtained for m a cos 2 β ≊ 2 − 6 meV, where m a is the mass of the axion and cos 2 β is a free parameter, and that values larger than 10 meV are clearly excluded.