Research in Astronomy and Astrophysics Trends of stellar entropy along stellar evolution

Abstract This paper is devoted to discuss the difference in the thermodynamic entropy budget per baryon in each type of stellar object found in Universe. We track and discuss the actual decrease of the stored baryonic thermodynamic entropy from the most prim-itive molecular cloud up to the final fate of matter in the black holes, passing through evolved states of matter as found in white dwarfs and neutron stars. We then discuss the case of actual stars of different masses throughout their evolution, clarifying the role of virial equilibrium condition for the decrease of the entropy and related issues. Finally, we discuss how gravity ultimately drives composition, hence structural changes along the stellar evolution all the way until the ultimate collapse to black holes, which may increase dramatically their entropy because of the gravitational contribution itself