The nature of the naked singularity in generalized Vaidya spacetime and white hole geodesics

Authors

DOI:

https://doi.org/10.33910/2687-153X-2021-2-1-33-40

Keywords:

generalized Vaidya spacetime, naked singularity, geodesics, matching, white hole geodesics, black hole

Abstract

This paper gives conditions to the energy-momentum tensor when the gravitational collapse of generalized Vaidya spacetime results in a naked singularity. We also consider the gravitational collapse of a matter cloud whose interior is described with Vaydia-de Sitter spacetime—when the collapse ends, this metric must be the de Sitter one, and the result of such a collapse is a so-called regular black hole. We provide the geodesic equations for the case when the matter is described with the equation of the state both P = −ρ and P = αρ, where α belongs to the interval (0,1/3]. We match these geodesics with geodesics in the Schwarzschild metric. We also explain the nature of white hole geodesics with either the naked singularity formation or the regular black hole formation.

References

Brassel, B. P., Goswami, R., Maharaj, S. D. (2017) Collapsing radiating stars with various equations of state. Physical Review D, 95 (12), article 124051. https://www.doi.org/10.1103/PhysRevD.95.124051 (In English)

Brassel, B. P., Maharaj, S. D., Goswami, R. (2017) Diffusive and dynamical radiating stars with realistic equations of state. General Relativity and Gravitation, 49 (3), article 37. https://www.doi.org/10.1007/s10714-017-2202-2 (In English)

Dawood, A. K., Ghosh, S. G. (2004) Generating dynamical black hole solutions. Physical Review D, 70 (10), article 104010. https://www.doi.org/10.1103/PhysRevD.70.104010 (In English)

Dymnikova, I. (1992) Vacuum nonsingular black hole. General Relativity and Gravitation, 24 (3), 235–242. https://doi.org/10.1007/BF00760226 (In English)

Dymnikova, I. (2002) The cosmological term as a source of mass. Classical and Quantum Gravity, 19 (4), 725–740. https://www.doi.org/10.1088/0264-9381/19/4/306 (In English)

Grib, A. A., Pavlov, Yu. V. (2015) Are black holes totally black? Gravitation and Cosmology, 21 (1), 13–18. https://www.doi.org/10.1134/S0202289315010065 (In English)

Grib, A. A., Pavlov, Yu. V., Vertogradov, V. D. (2014) Geodesics with negative energy in the ergosphere of rotating black holes. Modern Physics Letters A, 29 (20), article 1450110. https://www.doi.org/10.1142/S0217732314501107 (In English)

Hawking, S. W., Ellis, G. F. R. (1973) The large scale structure of space-time. London: Cambridge University Press, 385 p. https://doi.org/10.1017/CBO9780511524646 (In English)

Joshi, P. S. (2007) Gravitational collapse and spacetime singularities. Cambridge: Cambridge University Press, 269 p. https://doi.org/10.1017/CBO9780511536274 (In English)

Joshi, P. S., Malafarina, D. (2011) Recent developments in gravitational collapse and spacetime singularities. International Journal of Modern Physics D, 20 (14), 2641–2729. https://www.doi.org/10.1142/S0218271811020792 (In English)

Mkenyeleye, M. D., Goswami, R., Maharaj, S. D. (2014) Gravitational collapse of generalized Vaidya spacetime. Physical Review D, 90 (6), article 064034. https://www.doi.org/10.1103/PhysRevD.90.064034 (In English)

Nolan, B. C. (1999) Strengths of singularities in spherical symmetry. Physical Review D, 60 (2), article 024014. https://www.doi.org/10.1103/PhysRevD.60.024014 (In English)

Oppenheimer, J. R., Snyder, H. (1939) On continued gravitational contraction. Physical Review, 56 (5), 455–459. https://www.doi.org/10.1103/PhysRev.56.455 (In English)

Papapetrou, A. (1985) Formation of singularity and causality. In: N. Dadhich (ed.). A random walk in relativity and cosmology: Essays in honour of P C. Vaidaya and A. K. Raychaudhuri. New York: Wiley Publ., pp. 184–191. (In English)

Poisson, E. (2004) A relativist’s toolkit: The mathematics of black-hole mechanics. Cambridge: Cambridge University Press, 233 p. https://doi.org/10.1017/CBO9780511606601 (In English)

Tipler, F. J. (1977) Singularities in conformally flat spacetimes. Physics Letters A, 64 (1), 8–10. https://www.doi.org/10.1016/0375-9601(77)90508-4 (In English)

Vertogradov, V. D. (2015) Geodesics for particles with negative energy in Kerr’s metric. Gravitation and Cosmology, 21 (2), 171–174. https://www.doi.org/10.1134/S0202289315020115 (In English)

Vertogradov, V. D. (2016) Naked singularity formation in generalized Vaidya space-time. Gravitation and Cosmology, 22 (2), 220–223. https://www.doi.org/10.1134/S020228931602016X (In English)

Wang, A., Wu, Y. (1999) LETTER: Generalized vaidya solutions. General Relativity and Gravitation, 31 (1), 107–114. https://www.doi.org/10.1023/A:1018819521971 (In English)

Published

29.03.2021

Issue

Section

Theoretical Physics