Effects of CDTT Model on the Dynamical Instability of Cylindrically   Symmetric Collapsing Stars
  We assume cylindrically symmetric stars which begin collapsing by dissipating energy in the form of heat flux. We wish to study the effects of Carroll-Duvvuri-Trodden-Turner (CDTT) model, $f(R)=R+\sigma\frac{\mu^4}{R}$, on the range of dynamical instability. For this purpose, perturbation scheme is applied to all the metric functions, material functions and $f(R)$ model to obtain the full set of dynamical equation which control the evolution of the physical variables at the surface of a star. It is found that instability limit involves adiabatic index $\Gamma$ which depends on the density profile and immense terms of perturbed CDTT model. In addition, model is constrained by some requirement, e.g. positivity of physical quantities. We also reduce our results asymptotically as $\mu\rightarrow0$, being the GR results in both the Newtonian and post Newtonian regimes. 
Hafiza Rizwana Kausar
gr-qc