Can gravitational vacuum condensate stars be a dark energy source?

Understand

Gravitational vacuum condensate stars, also known as gravastars, have been proposed as an alternative to black holes.

• Their interior contains a perfect fluid with an equation of state akin to that of a cosmological constant.
• For this reason, they have recently been considered as a possible astrophysical source of dark energy.
• In this work we argue that gravitational vacuum condensate stars cannot be the source of dark energy and highlight that a direct coupling of their mass to the dynamics of the Universe would lead to an additional velocity dependent acceleration, damping their motion with respect to the cosmological frame.