Nonextensivity in the Solar Neighborhood
  In the present study, we analyze the radial velocity distribution as a function of different stellar parameters such as stellar age, mass, rotational velocity and distance to the Sun for a sample of 6781 single low--mass field dwarf stars, located in the solar neighborhood. We show that the radial velocity distributions are best fitted by $q$--Gaussians that arise within the Tsallis nonextensive statistics. The obtained distributions cannot be described by the standard Gaussian that emerges within Boltzmann-Gibbs (B--G) statistical mechanics. The results point to the existence of a hierarchical structure in phase space, in contrast to the uniformly occupied phase space of B--G statistical mechanics, driven by the $q$--Central Limit Theorem, consistent with nonextensive statistical mechanics. 
D. B. de Freitas and J. R. De Medeiros
astro-ph.SR