학술논문

Updating the theoretical tidal evolution constants: Apsidal motion and the moment of inertia
Document Type
Working Paper
Source
A&A 2019
Subject
Astrophysics - Solar and Stellar Astrophysics
Language
Abstract
The theoretical apsidal motion constants are key tools to investigate the stellar interiors in close eccentric binary systems. In addition, these constants and the moment of inertia are also important to investigate the tidal evolution of close binary stars as well as of exo-planetary systems. The aim of the paper is to present new evolutionary models, based on the MESA package, that include the internal structure constants (k$_2$, k$_3$, and k$_4$), the radius of gyration, and the gravitational potential energy for configurations computed from the pre-main-sequence (PMS) up to the first ascent giant branch or beyond. The calculations are available for the three metallicities [Fe/H]= 0.00, -0.50, and -1.00, which take the recent investigations in less metallic environments into account. This new set of models replaces the old ones, published about 15 years ago, using the code GRANADA. Core overshooting was taken into account using the mass-f$_{ov}$ relationship, which was derived semi-empirically for models more massive than 1.2 M$_{\odot}$. The differential equations governing the apsidal motion constants, moment of inertia, and the gravitational potential energy were integrated simultaneously through a fifth-order Runge-Kutta method with a tolerance level of 10$^{-7}$. The resulting models (from 0.8 up to 35.0 M$_{\odot}$) are presented in 54 tables for the three metallicities, containing the usual characteristics of an evolutionary model (age, initial masses, log T$_{\rm eff}$, log g, and log L), the constants of internal structure (k$_2$, k$_3$, and k$_4$), the radius of gyration $\beta,$ and the factor $\alpha$ that is related with the gravitational potential energy.