A model for a possible variable cosmic object is presented. The model consists of a massive shell surrounding a compact object. The gravitational and self-gravitational forces tend to collapse the shell, but the internal tangential stresses oppose the collapse. The combined action of the two types of forces is studied and several cases are presented. In particular, we investigate the spherically symmetric case in which the shell oscillates radially around a central compact object.
free text keywords: Space and Planetary Science, Astronomy and Astrophysics, Astronomy, Astrophysics, COSMIC cancer database, Oscillation, Physics, Dense matter, General Relativity and Quantum Cosmology