Diquark stars with extended scalar diquarks and their stability

Within the framework of an effective -theory, an attempt is made to study diquark stars and their stability with extended scalar diquarks (ESD). In this context, an equation of state (EOS) for the ESD gas is obtained. We find the EOS for the ESD gas to be stiffer than that for a point-like diquark and/or quark gas. This EOS is then used to investigate various properties of the diquark stars. In particular, the mass and radius of the maximum mass star with ESD matter turn out to be larger than those obtained with point-like diquark and/or quark matter. However, they are in conformity with the predictions available for soliton and boson stars. The stability of ESD stars against radial oscillations is also investigated. Received: 18 May 1999 / Revised version: 19 November 1999 / Published online: 14 April 2000