Neutron Stars and Gravitational Scalars
Abstract
The structure of neutron stars is investigated in the context of a scalartensor theory of gravity with variable BransDicke parameter omega(phi). Neutron star models are constructed using the Pandharipande (hyperon) equation of state and an equation of state that maximizes the mass for various values of a variability parameter alpha. It is shown that the neutron stars are more compact and less massive than their counterparts in general relativity and standard BransDicke theory. The compactness of an astrophysical body is generally measured by its sensitivity to changes in the gravitational constant and is important in the analysis of the orbital motion in close binary systems. This paper gives a more general definition for this sensitivity in a general scalartensor theory, and dependence on alpha is calculated. The effects can be quite significant even for omega greater than 500 and alpha within the experimental bounds, and can therefore provide a window for testing scalartensor theories of gravity that are indistinguishable from general relativity in the solar system.
 Publication:

The Astrophysical Journal
 Pub Date:
 July 1992
 DOI:
 10.1086/171537
 Bibcode:
 1992ApJ...393..685Z
 Keywords:

 Neutron Stars;
 Relativistic Theory;
 Stellar Gravitation;
 Stellar Structure;
 Binary Stars;
 Scalars;
 Stellar Mass;
 String Theory;
 Tensor Analysis;
 Astrophysics;
 GRAVITATION;
 RELATIVITY;
 STARS: NEUTRON