Open AccessAntonov problem and quasi‐equilibrium states in an N ‐body system
Author(s) -
Taruya Atsushi,
Sakagami Masaaki
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.09635.x
Subject(s) - physics , polytropic process , adiabatic process , statistical physics , thermal equilibrium , many body problem , thermodynamic equilibrium , sequence (biology) , three body problem , stellar evolution , classical mechanics , astrophysics , stars , thermodynamics , quantum mechanics , biology , genetics
ABSTRACT In this paper, a quantitative characterization of the evolutionary sequence of a stellar self‐gravitating system is investigated, focusing on the pre‐collapse stage of the long‐term dynamical evolution. In particular, we consider the quasi‐equilibrium behaviour of N ‐body systems in the setup of the so‐called Antonov problem, i.e. a self‐gravitating N ‐body system confined within an adiabatic wall, and try to seek a possible connection with the thermostatistics of self‐gravitating systems. For this purpose, a series of long‐term N ‐body simulations with various initial conditions are performed. We found that a quasi‐equilibrium sequence away from thermal equilibrium can be characterized by a one‐parameter family of stellar models. Especially, a stellar polytropic distribution satisfying the effective equation of state P ∝ρ 1+1/ n provides an excellent approximation to the evolutionary sequence of the N ‐body system. Based on the numerical results, we discuss the link between the quasi‐equilibrium state and the generalized thermostatistics by means of the non‐extensive entropy.