Publication: Is gravitational collapse possible in f(R) gravity?
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Amer Physical Soc
Gravitational collapse is still poorly understood in the context of f(R) theories of gravity, since the Oppenheimer-Snyder model is incompatible with their junction conditions. In this work, we will present a systematic approach to the problem. Starting with a thorough analysis of how the Oppenheimer-Snyder construction should be generalized to fit within metric f(R) gravity, we shall subsequently proceed to explore the existence of novel exterior solutions compatible with physically viable interiors. Our formalism has allowed us to show that some paradigmatic vacuum metrics cannot represent spacetime outside a collapsing dust star in metric f(R) gravity. Moreover, using the junction conditions, we have found a novel vacuole solution of a large class of f(R) models, whose exterior spacetime is documented here for the first time in the literature as well. Finally, we also report the previously unnoticed fact that the Oppenheimer-Snyder model of gravitational collapse is incompatible with the junction conditions of the Palatini formulation of f(R) gravity.
© 2022 American Physical Society. We would like to thank Jose Beltran Jimenez and Rituparno Goswami for their very insightful comments. This research is partly supported by the Spanish Ministerio de Ciencia e Innovacion (MICINN) under the research Grant No. PID2019-108655 GB-I00. A. C.-T. is supported by a Universidad Complutense de Madrid-Banco Santander predoctoral contract CT63/19-CT64/19. A. d. l. C.-D. acknowledges support from South African NRF Grants No. 120390, reference: BSFP190416431035; No. 120396, reference: CSRP190405427545; and Spanish MICINN Grants PID2019-108655 GB-I00 and COOPB204064, I-COOP+2019.