The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The gravitational behaviour of a dense compact object is studied in isotropic coordinates. We obtain new classes of static, spherically symmetric classes of solutions to the Einstein–Maxwell field equations by assuming an anisotropic pressures and a barotropic equation of state which is polytropic. Four new classes of exact solutions are found with different polytropic indices. We can regain masses...