Gravitational collapse in generalized K-essence emergent Vaidya spacetime via f(R,T) gravity

This study focuses on investigating the collapse possibilities of the generalized emergent Vaidya spacetime within the framework of f (R,T ) gravity, specifically in the setting of K-essence theory. The Dirac-Born-Infeld type non-standard Lagrangian is used in this work to determine the emergent metric Ḡµν, which is not conformally equal to the usual gravitational metric. Here, we employ the function f (R,T ) to represent the additive character of the emergent Ricci scalar (R) and trace of the emergent energy-momentum tensor (T). In our analysis, it can be shown that certain selections of f (R,T ) can lead to the presence of a naked singularity resulting from gravitational collapse. Additionally, alternative choices of f (R,T ) were found to yield an accelerating universe primarily governed by dark energy. In addition, the investigation revealed the existence of both positive and negative masses, which can be understood as a gravitational dipole. It is also found that the K-essence theory has the potential to serve as both a dark energy framework and a simple gravitational theory at the same time, allowing for the investigation of a wide range of cosmological phenomena.

Arijit Panda, Goutam Manna, Saibal Ray, Maxim Khlopov, Md Rabiul Islam