Is scalar-tensor gravity consistent with polytropic stellar models?

Abstract

We study the scalar field potential $V(\varphi )$ in the scalar-tensor gravity with self-consistent polytropic stellar configurations. Without choosing a particular potential, we numerically derive the potential inside various stellar objects. We restrict the potential to conform to general relativity or to $f(R)$ gravity inside and require the solution to arrive at SdS vacuum at the surface. The studied objects are required to obtain observationally valid masses and radii corresponding to solar type stars, white dwarfs and neutron stars. We find that the resulting scalar-tensor potential $V(\varphi )$ for the numerically derived polytrope that conforms to general relativity, in each object class, is highly dependent on the matter configuration as well as on the vacuum requirement at the boundary. As a result, every stellar configuration arrives at a potential $V(\varphi )$ that is not consistent with the other stellar class potentials. Therefore, a general potential that conforms to all these polytropic stellar classes could not be found.

6 pages, 2 figures, text revised and some concepts clarified, results unchanged

References in corpus (17)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Dark Energy and the Accelerating Universe
• Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
• Disappearing cosmological constant in f(R) gravity
• Modified f(R) gravity consistent with realistic cosmology: from matter dominated epoch to dark energy universe
• Avoiding Dark Energy with 1/R Modifications of Gravity
• The Large Scale Structure of f(R) Gravity
• Evading Equivalence Principle Violations, Cosmological and other Experimental Constraints in Scalar Field Theories with a Strong Coupling to Matter
• f(R) Gravity and Chameleon Theories
• Modified non-local-F(R) gravity as the key for the inflation and dark energy
• Matter instability in modified gravity
• The (pseudo)issue of the conformal frame revisited
• Collapsing spherical stars in f(R) gravity
• Static spherically symmetric perfect fluid solutions in $f(R)$ theories of gravity
• Theory of gravitation theories: a no-progress report
• Stellar configurations in f(R) theories of gravity
• Stability of Polytropes