caa a22 4500 445387602 CHVBK 20180317143036.0 cr unu---uuuuu 170323e20111101xx s 000 0 eng 10.1007/s10714-011-1216-4 doi (NATIONALLICENCE)springer-10.1007/s10714-011-1216-4 Naked singularity formation in $${f({\mathcal R})}$$ gravity [Elektronische Daten] [A. Ziaie, K. Atazadeh, S. Rasouli] We study the gravitational collapse of a star with barotropic equation of state p=wρ in the context of $${f({\mathcal R})}$$ theories of gravity. Utilizing the metric formalism, we rewrite the field equations as those of Brans-Dicke theory with vanishing coupling parameter. By choosing the functionality of Ricci scalar as $${f({\mathcal R})=\alpha{\mathcal R}^{m}}$$ , we show that for an appropriate initial value of the energy density, if α and m satisfy certain conditions, the resulting singularity would be naked, violating the cosmic censorship conjecture. These conditions are the ratio of the mass function to the area radius of the collapsing ball, negativity of the effective pressure, and the time behavior of the Kretschmann scalar. Also, as long as parameter α obeys certain conditions, the satisfaction of the weak energy condition is guaranteed by the collapsing configuration. Springer Science+Business Media, LLC, 2011 Naked singularity nationallicence $${f({\mathcal R})}$$ gravity nationallicence Ziaie A. Department of Physics, Shahid Beheshti University, Evin, 19839, Tehran, Iran aut Atazadeh K. Department of Physics, Shahid Beheshti University, Evin, 19839, Tehran, Iran aut Rasouli S. Department of Physics, Shahid Beheshti University, Evin, 19839, Tehran, Iran aut General Relativity and Gravitation Springer US; http://www.springer-ny.com 43/11(2011-11-01), 2943-2963 0001-7701 43:11<2943 2011 43 10714 https://doi.org/10.1007/s10714-011-1216-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10714-011-1216-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ziaie A. Department of Physics, Shahid Beheshti University, Evin, 19839, Tehran, Iran aut NATIONALLICENCE 700 1- Atazadeh K. Department of Physics, Shahid Beheshti University, Evin, 19839, Tehran, Iran aut NATIONALLICENCE 700 1- Rasouli S. Department of Physics, Shahid Beheshti University, Evin, 19839, Tehran, Iran aut NATIONALLICENCE 773 0- General Relativity and Gravitation Springer US; http://www.springer-ny.com 43/11(2011-11-01), 2943-2963 0001-7701 43:11<2943 2011 43 10714 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer