Rubab Manzoor2018-10-152018-10-152016Sharif, M., & Manzoor, R. (2016). Instability analysis of a cylindrical stellar object in brans–dicke gravity. Journal of Experimental and Theoretical Physics, 149(5), 849-858. (Rubab Manzoor (Mathematics /SSC), JCR LISTED (IF:0:953))https://escholar.umt.edu.pk/handle/123456789/3243This paper investigates instability ranges of a cylindrically symmetric collapsing cosmic filamentary structure in Brans-Dicke theory of gravity. For this purpose, we use perturbation approach in the modified field equations as well as dynamical equations and construct a collapse equation. The collapse equation with adiabatic index (Γ) is used to explore the instability ranges of both isotropic as well as anisotropic fluid in Newtonian and post-Newtonian approximations. It turns out that the instability ranges depend on the dynamical variables of collapsing filaments. We conclude that the system always remains unstable for 0 < Γ < 1 while Γ > 1 provides instability only for the special case.enMathematicsBrans-Dicke theory; Instability; Newtonian and post-Newtonian regimesArticle