2013/08/31 by J. R. P. Silva, Jose R. P. Silva, M. M. F. Nepomuceno +5
Economics, Econometrics and Finance · Physics and Astronomy · #Angular momentum #Angular velocity #Astrophysics #Boltzmann distribution #Classical mechanics #Complex Systems and Time Series Analysis #Distribution function #Formalism (music) #Physics #Stars #Statistical Mechanics and Entropy #Statistical physics #Stellar, planetary, and galactic studies #Thermodynamics #Tsallis statistics #astro-ph.SR
paper · pdf · doi:10.1088/0004-637x/777/1/20
7 pages, 4 figures. Published in ApJ
openalex publication_date 2013/10/09 · arxiv created 2013/12/09 · arxiv updated 2013/12/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Nonextensive formalism is a generalization of the Boltzmann–Gibbs statistics. In this formalism, the entropic index q is a quantity characterizing the degree of nonextensivity and is interpreted as a parameter of long-memory or long-range interactions between the components of the system. Since its proposition in 1988, this formalism has been applied to investigate a wide variety of natural phenomena. In stellar astrophysics, a theoretical distribution function based on nonextensive formalism ( q distributions) has been successfully applied to reproduce the distribution of stellar radial and rotational velocity data. In this paper, we investigate the time variation of the entropic index q obtained from the distribution of rotation, V sin i , for a sample of 254 rotational data for solar-type stars from 11 open clusters aged between 35.5 Myr and 2.6 Gyr. As a result, we have found an anti-correlation between the entropic index q and the age of clusters, and that the distribution of rotation V sin i for these stars becomes extensive for an age greater than about 170 Myr. Assuming that the parameter q is associated with long-memory effects, we suggest that the memory of the initial angular momentum of solar-type stars can be scaled by the entropic index q . We also propose a physical link between the parameter q and the magnetic braking of stellar rotation.