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In this paper, we have studied gravitational collapse and expansion of nonstatic anisotropic fluid in

In the gravitational study of more than four dimensions, the unification problem of gravity with electromagnetism and other basic connections are discussed by [

In recent years, the higher-order gravity included higher derivative curvature terms, which is an interesting and developing study. The most widely studied theory in the higher curvature gravities is known as Einstein-Gauss-Bonnet (EGB) theory of gravity. The EGB theory of gravity is a special case of the Lovelocks gravity. The Lagrangian of EGB gravity was obtained from the first three terms of Lagrangian of the Lovelock theory. Pedro [

In the composition of stars, the nuclear matter is enclosed inside the stars. The stars are gravitated and attracted continuously to the direction of their center because of gravitational interaction of their matter particles; this phenomenon is known as gravitational contraction of stars, which leads to gravitational collapse. It is studied in [

Zubair et al. [

Oppenheimer and Snyder [

In Section

We start with the

For the different values of

The expansion scalar must be negative in case of the collapse, so for

The energy conditions for the curvature matter coupled gravity are

Null energy condition:

Weak energy condition:

Strong energy condition:

In this case, we analyzed our results for time profile

Plot of density along

Behavior of radial pressure along

Tangential pressure along

Mass plot along

Plot of anisotropy parameter along

Plot of energy conditions along

In this case, the expansion scalar

For

In this case, we take

Density behavior along

Radial pressure behavior along

Tangential pressure behavior along

Mass behavior along

Anisotropy parameter behavior for

Plot of energy conditions along

There has been a great interest in studying the relativistic anisotropic systems due to the existence of such systems in the astronomical objects. The exact solutions of anisotropic sphere are helpful to determine the anisotropy of the universe during any era. Barrow and Maartens [

The EGB gravity theory is the low energy limits of super-symmetric string theory of gravity [

The aim of this paper is to study the generating solutions for anisotropic spherical symmetric fluid in

We assume that the areal radius

The dynamics of the spherical fluid are discussed in both cases. The density of the matter is decreasing/increasing in collapse/expansion with the arbitrary choice of constant/parameter, time profile, and different values of GB term

The data used to support the findings of this study are available from the corresponding author upon request.

The authors declare that there are no conflicts of interest regarding the publication of this manuscript.

One of the authors, G. Abbas, acknowledges the financial support from HEC, Islamabad, Pakistan, under NRPU project with Grant no. 20-4059/NRPU/R&D/HEC/14/1217.