# Role of equation of states and thermodynamic potentials in avoidance of trapped surfaces in gravitational collapse

## TL;DR

This paper explores a gravitational collapse model where a star radiates energy without forming trapped surfaces or horizons, ending in flat spacetime, highlighting the importance of equations of state and thermodynamic bounds.

## Contribution

It introduces a novel collapse scenario avoiding trapped surfaces, emphasizing the role of thermodynamic potentials and equations of state in such models.

## Key findings

- Collapse ends in flat spacetime without trapped surfaces
- Models are generic for a range of initial data and equations of state
- Potential observational signatures detectable by radio telescopes

## Abstract

In this paper we consider the novel scenario where a spherically symmetric perfect fluid star is undergoing continual gravitational collapse while continuously radiating energy in an exterior radiating spacetime. There are no trapped surfaces and the collapse ends to a flat spacetime. Also the collapsing matter obeys the weak and dominant energy conditions at all epoch. Our analysis transparently brings out the role of the equation of state as well as the bounds on the thermodynamic potentials to realise such a scenario. We argue that, since the system of Einstein field equations allows for such a scenario for an open set of initial data as well as the equation of state function in their respective functional spaces, these models are generic and devoid of the problems and paradoxes related to horizons and singularities. The recent high resolution radio telescopes should in principle detect the presence of these compact objects in the sky.