Structure coefficients of high-mass stars

Abstract

Variation in internal structure constants k(j), g(j), D-j of zero-age main sequence model stars larger than 50 M-circle dot mass according to metallicity and mass are investigated. A series of stellar models of mass between 50 and 100 M-circle dot with metallicities between Z = 0:0001 and Z = 0:03 are utilized. For each model, the coefficients are obtained by Clairaut-Radau's differential equation. The Eggleton stellar models are used in EZ-Web compilation. The results are interesting for high metal values. We investigate that how the apsidal motion constant k(2) changes for evolved stars. In this context, we have computed the constant k(2) theoretically depending on stellar age for the eccentric eclipsing massive binaries, HD 152218 and HD 152248. Comparison of the models with observational data was made for stars below 50 M-circle dot. Since there are few studies to calculate internal structure coefficients for stellar models with masses >50 M-circle dot, these results will guide the future theoretical and observational studies for very massive stars.