In this Letter we have derived the Jeans length in the context of the Kaniadakis statistics. We have compared this result with the Jeans length obtained in the non-extensive Tsallis statistics and discussed the main differences between these two models. We have also obtained the κ-sound velocity. Finally, we have applied the results obtained here to analyze an astrophysical system.
Keywords: Jeans' criterion; non-gaussian statisticsThe dynamical stability of a self-gravitating system usually can be described by the Jeans criterion of gravitational instability. The so-called Jeans's length [1] is given bywhere k B is the Boltzmann constant, T is the temperature, µ is the mean molecular weight, m H is the atomic mass of hydrogen, G is the gravitational constant and ρ 0 is the equilibrium mass density. The critical value λ J , Eq. (1), is derived by considering a small perturbation in a set of four equations that are the equation of continuity, the Euler's equation, the Poisson's equation and the equation of state of an ideal gas. The Jeans length establishes that if the wave length λ of density fluctuation is greater than λ J then the density will grow with time in an exponential form and the system will become gravitationally unstable. For more details see Jiulin in ref.[2]. Tsallis [3] has proposed an important extension of the Boltzman-Gibbs (BG) statistical theory. In a brief and technical terminology, this model is also currently referred to as a nonextensive (NE) statistical mechanics.Tsallis thermostatistics formalism defines a nonadditive entropy aswhere p i is the probability of the system to be in a microstate, W is the total number of configurations and q, known in the current literature as being the Tsallis * Electronic address: evertonabreu@ufrrj.br † Electronic address: jorge@fisica.ufjf.br ‡ Electronic address: edesiobarboza@uern.br § Electronic address: nunes@ecm.ub.edu parameter or NE parameter, is a real parameter which quantifies the degree of nonextensivity. The definition of entropy in Tsallis statistics carries the usual properties of positivity, equiprobability, concavity and irreversibility and it also has motivated the study of multifractals systems. It is important to stress that Tsallis thermostatistics formalism contains the BG statistics as a particular case in the limit q → 1 where the usual additivity of entropy is recovered. Plastino and Lima [4] have derived a NE equipartition law of energy. It has been shown that the kinetic foundations of Tsallis' NE statistics leads to a velocity distribution for free particles given by [5] where B q is a normalization constant. Then, the expectation value of v 2 , for each degree of freedom, is given byThe equipartition theorem is then obtained by using thatand we will arrive atThe range of q is 0 ≤ q < 5/3. For q = 5/3 (critical value) the expression of the equipartition law of energy, Eq. (6), diverges. It is also easy to observe that for q = 1, the classical equipartition theorem for each microscopic degrees of freedom can be recovered.