Year: 2004
Type: article
Abstract: We study analytically and numerically the evolution of bound systems in universes with accelerating expansion where the acceleration either increases with time towards a Big Rip singularity (phantom cosmologies) or decreases with time (quintessence). We confirm the finding of Caldwell et al. [R. R. Caldwell, M. Kamionkowski and N. N. Weinberg, Phys. Rev. Lett. 91, 071301 (2003).] that bound structures get dissociated in phantom cosmologies but we demonstrate that this happens earlier than anticipated in Ref. [R. R. Caldwell, M. Kamionkowski and N. N. Weinberg, Phys. Rev. Lett. 91, 071301 (2003).]. In particular we find that the ``rip time'' when a bound system gets unbounded is not the time when the repulsive phantom energy gravitational potential due to the average $(\ensuremath{\rho}+3p)$ balances the attractive gravitational potential of the mass M of the system. Instead, the ``rip time'' is the time when the minimum of the time-dependent effective potential (including the centrifugal term) disappears. For the Milky Way galaxy this happens approximately 180 Myrs before the Big Rip singularity instead of approximately 60 Myrs indicated in [R. R. Caldwell, M. Kamionkowski and N. N. Weinberg, Phys. Rev. Lett. 91, 071301 (2003).] for a phantom cosmology with $\mathrm{w}=\ensuremath{-}1.5$. A numerical reconstruction of the dissociating bound orbits is presented.
Authors: S. Nesseris, L. Perivolaropoulos
Institution: University of Ioannina
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2080116030