Astronomy and Astrophysics – Astrophysics – General Relativity and Quantum Cosmology
Scientific paper
2007-04-20
Phys.Rev.D76:024020,2007
Astronomy and Astrophysics
Astrophysics
General Relativity and Quantum Cosmology
Published version, 12 pages, 7 figures
Scientific paper
10.1103/PhysRevD.76.024020
We study both analytically and numerically the gravitational fields of stars in f(R) gravity theories. We derive the generalized Tolman-Oppenheimer-Volkov equations for these theories and show that in metric f(R) models the Parameterized Post-Newtonian parameter $\gamma_{\rm PPN} = 1/2$ is a robust outcome for a large class of boundary conditions set at the center of the star. This result is also unchanged by introduction of dark matter in the Solar System. We find also a class of solutions with $\gamma_{\rm PPN} \approx 1$ in the metric $f(R)=R-\mu^4/R$ model, but these solutions turn out to be unstable and decay in time. On the other hand, the Palatini version of the theory is found to satisfy the Solar System constraints. We also consider compact stars in the Palatini formalism, and show that these models are not inconsistent with polytropic equations of state. Finally, we comment on the equivalence between f(R) gravity and scalar-tensor theories and show that many interesting Palatini f(R) gravity models can not be understood as a limiting case of a Jordan-Brans-Dicke theory with $\omega \to -3/2$.
Kainulainen Kimmo
Piilonen Johanna
Reijonen Vappu
Sunhede Daniel
No associations
LandOfFree
Spherically symmetric spacetimes in f(R) gravity theories does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Spherically symmetric spacetimes in f(R) gravity theories, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spherically symmetric spacetimes in f(R) gravity theories will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-573800