IALP   13078
INSTITUTO DE ASTROFISICA LA PLATA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
The cooling of white dwarfs a a varying gravitational constant
Autor/es:
E. GARCÍA-BERRO; L. G. ALTHAUS; S. TORRES; P. LORÉN-AGUILAR; A. H. CÓRSICO; J. ISERN
Reunión:
Simposio; JENAM 2010 symposium: From varying couplings to fundamental physics; 2010
Resumen:
Within the theoretical  framework of some modern unification theories   the  constants   of  nature   are   functions  of cosmological  time.   Since  white  dwarfs  are  long-lived,          compact  objects, they  offer the  possibility of  testing a possible variation of  the gravitational constant and, thus, to  place constraints  to these  theories.  We  present full white dwarf  evolutionary calculations in the  case in which the gravitational  constant $G$ decreases  with time.  White dwarf  evolution  is  computed  in  a  self-consistent  way, including   the  most   up-to-date  physical   inputs.   The evolutionary sequences also consider accurate outer boundary conditions  provided  by non-gray  model  atmospheres and  a detailed  core chemical  composition that  results  from the calculation of  the full evolution of  progenitor stars.  We find that the mechanical structure and the energy balance of the white dwarf  are strongly modified by the  presence of a varying  $G$. In  particular, for  a rate  of change  of $G$ larger than $\dot{G}/G$=$-1  \times 10^{-12}$ yr$^{-1}$, the evolution  of cool  white dwarfs  is markedly  affected. The impact of  a varying  $G$ is more  notorious in the  case of more massive white dwarfs.