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Exact solutions for spherical gravitational collapse around a black hole:the effect of tangential pressure

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Chinese Physics C 2018年第8期42卷 167-173页

作者：赵声贤张双南 Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Particle Astrophysics Institute of High Energy Physics

Spherical gravitational collapse towards a black hole with non-zero tangential pressure is *** solutions corresponding to different equations of state are *** find that when taking the tangential pressure into account,the exact solutions have three qualitatively different *** positive tangential pressure,the shell around a black hole may eventually collapse onto the black hole,or expand to infinity,or have a static but unstable solution,depending on the combination of black hole mass,mass of the shell and the pressure *** vanishing or negative pressure,the shell will collapse onto the black *** all eventually collapsing solutions,the shell will cross the event horizon,instead of accumulating outside theeventhorizon,even if clocked by a distant stationary observer.

关键词： black holes gravitational collapse general relativity

Spherical gravitational collapse in f(R) Gravity with Linear Equation of State

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Communications in Theoretical Physics 2018年第8期69卷 185-189页

作者： Zahid Ahmad Hassan Shah Suhail Khan Department of Mathematics COMSATS Institute of Information Technology Department of Mathematics University of Peshawar

In a paper [Gen. Relativ. Gravit. 48(2016) 57] Chakrabarti and Banerjee investigated perfect fluid collapse in f(R) gravity model and claimed that such a collapse is possible. In this paper we show that without the assumption of dark energy it is not possible that perfect fluid spherical gravitational collapse will occur. We have solved the field equations by assuming linear equation of state(p = ωμ) in metric f(R) gravity with ω =-1. It is shown that Chakrabarti and Banerjee reached to false conclusion as they derived wrong field equations. We have also discussed formation of apparent horizon and singularity.

关键词： gravitational collapse matching conditions dark energy apparent horizon

New Solutions of gravitational collapse in General Relativity and in the Newtonian Limit

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Journal of High Energy Physics, Gravitation and Cosmology 2022年第2期8卷 457-485页

作者： Jan Helm Technical University of Berlin Berlin Germany

We discuss the Oppenheimer-Snyder-Datt (OSD) solution from a new perspective, introduce a completely new formulation of the problem exclusively in external Schwarzschild space-time (ESM) and present a new treatment of the singularities in this new formulation. We also give a new Newtonian approximation of the problem. Furthermore, we present new numerical solutions of the modified OSD-model and of the ball-to-ball-collapse with 4 different numerical methods.

关键词： General Relativity gravitational collapse External Schwarzschild Space-Time

The stability of a shearing viscous star with an electromagnetic field

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Chinese Physics B 2013年第5期22卷 175-181页

作者： M. Sharif msharif.math@pu.edu.pk azammath@*** Division of Science and Technology University of Education Township Campus Lahore-54590 Pakistan

We analyze the role of the electromagnetic field for the stability of a shearing viscous star with spherical symmetry. Matching conditions are given for the interior and the exterior metrics. We use a perturbation scheme to construct the collapse equation. The range of instability is explored in Newtonian and post Newtonian （pN） limits. We conclude that the electromagnetic field diminishes the effects of the shearing viscosity in the instability range and makes the system more unstable in both Newtonian and post Newtonian approximations.

关键词： gravitational collapse electromagnetic field instability

Emission of Phonons from a Rotating Sonic Black Hole

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Chinese Physics Letters 2014年第1期31卷 25-28页

作者：方恒忠周开虎 College of Science China University of Petroleum Qingdao 266580

We investigate the Hawking radiation from a rotating acoustic black hole. The phonon emission is calculated by using two methods and the same results are obtained. The contribution of the time coordinate to the phonon radiation is also discussed, which cannot be ignored for the coordinate systems that are not well-behaved at the horizon.

关键词： HAWKING radiation BLACK holes (Astronomy) gravitational collapse CELESTIAL reference systems HORIZON SPHERICAL astronomy

Mesozoic contraction deformation in the Yanshan and northern Taihang mountains and its implications to the destruction of the North China Craton

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Science China Earth Sciences 2011年第6期54卷 798-822页

作者： ZHANG ChangHou LI ChengMing DENG HongLing LIU Yang LIU Lei WEI Bo LI HanBin LIU Zi State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083 China

Mesozoic contraction deformation in the Yanshan and Taihang mountains is characterized by basement-involved thrust tectonics,basement-cored buckling anticlines and ductile thrust and nappe *** of these deformations are orientated west-east,west-northwest and northeast to *** contraction deformations began in the Permian,continued through the Triassic and Jurassic and terminated in the Early Cretaceous,and constitute an important part of the destruction of the North China *** is estimated,from balanced cross-section reconstructions,that the north-south shortening of the central part of the Yanshan belt before 135 Ma was around 38%.The initial crust thickness,pre-dating the major contraction deformation in late Paleozoic and early Mesozoic,was estimated to be around 35 km based on paleogeographic *** that the inferred depth of ductile thrusting deformation,20-25 km,was the crust thickness involved in the contraction deformation,and also assuming that the N-S contraction deformation was accommodated by vertical crust thickening,the thickness of the crust after the contraction deformation was expected to be around 47-50 *** was the approximate crust thickness required for the eclogitization of the lower crust for *** gravity potential accumulated by the isostatic uplift of the thickened crust,together with the decrease in crustal strength caused by the coeval magmatisms associated with the contraction deformation,led to the subsequent extensional collapse of the middle and upper crust although the regional stress regime associated with the plate interactions remained *** is inferred that the Mesozoic contraction deformations in the Yanshan and Taihang mountains were not only a significant tectonic process contributing to the destruction of the craton in middle and upper crust but also stimulated delamination at a deep level and the extension of the shallow *** other words,both the suspec

关键词： North China Craton Yanshan belt Taihang Mountain contraction deformation gravitational collapse

Deformation geometry and timing of the Wupoer thrust belt in the NE Pamir and its tectonic implications

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Frontiers of Earth Science 2016年第4期10卷 751-760页

作者： Xiaogan CHENG Hanlin CHEN Xiubin LIN Shufeng YANG Shenqiang CHEN Fenfen ZHANG Kang LI Zelin LIU School of Earth Sciences Zhejiang University Hangzhou 310027 China Research Center for Structures in Oil- and Gas-Bearing Basins Ministry of Education Hangzhou 310027 China Department of Exploration Geophysics College of Geophysics and Information Engineering China University of Petroleurn-Beijing Beijing 102249 China

The Pamir region, located to the northwest of the Tibetan Plateau, provides important information that can aid the understanding of the plateau＇s tectonic evolution. Here we present new findings on the deforma- tion geometry and timing of the Wupoer thrust belt at the northeastem margin of Pamir. Field investigations and interpretations of seismic profiles indicate that the eastern portion of the Wupoer thrust belt is dominated by an underlying foreland basin and an overlying piggy-back basin. A regional unconformity occurs between the Pliocene （N2） and the underlying Miocene （NI） or Paleogene （Pg） strata associated with two other local unconformities between Lower Pleistocene （Q1） and N2 and between Middle Pleistocene （Q2-4） and Q1 strata. Results of structural restorations suggest that compres- sional deformation was initiated during the latest Miocene to earliest Pliocene, contributing a total shortening magnitude of 48.6 km with a total shortening rate of 48.12%, most of which occurred in the period from the latest Miocene to earliest Pliocene. These results, com- bined with previous studies on the Kongur and Tarshkor- gan extensional system, suggest an interesting picture of strong piedmont compressional thrusting activity concur- rent with interorogen extensional rifting. Combining these results with previously published work on the lithospheric architecture of the Pamir, we propose that gravitational collapse drove the formation of simultaneous extensional and compressional structures with a weak, ductile middle crustal layer acting as a decollement along which both the extensional and compressional faults merged.

关键词： Pamir Kongur Wupoer gravitational collapse fold-and-thrust belt

Survival Conditions of Folding in Different Depth During Orogenesis-Deformation in Texas Creek and Chester Dome, USA

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Acta Geologica Sinica(English Edition) 2014年第1期88卷 103-112页

作者： CAO Hui XU Cuiping State Key Laboratory for Continental Tectonics and Dynamics Institute of Geology Chinese Academy of Geological Sciences School of Earth and Environmental Sciences James Cook University

A succession of 5 FIA trends（foliation intersection or inflection axes in porphyroblasts） preserved in high temperature-low pressure regime PreCambrian rocks in the Texas Creek, Arkansas River region reflected by the fold axial plane traces and schistosity data in this region. Similar fold axial plane trace data measured in Palaeozoic rocks in Chester Dome, Vermont, which is high temperature to medium pressure regime, only preserve the effects of the youngest FIAs of the all 5 FIA sets that obtained in this region. The other three FIA sets have no equivalent fold axial planes. This difference from shallow to deeper orogenic regimes reflects decreasing competency at greater pressure with collapse and unfolding of earlier formed folds. The greater overlying load of rocks has tended to flatten all but the very largest early-formed structures, preserving only those folds that were more recently developed.

关键词： orogenesis fold axial plane foliation intersection or inflection axes gravitational collapse porphyroblast

Normal Faulting Type Earthquake Activities in the Tibetan Plateau and Its Tectonic Implication

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Acta Geologica Sinica(English Edition) 2010年第1期84卷 135-144页

作者： XU Jiren ZHAO Zhixin Institute of Geology Chinese Academy of Geological Sciences Beijing 100037

This paper analyzes various earthquake fault types, mechanism solutions, stress field as well as other geophysical data to study the crust movement in the Tibetan plateau and its tectonic implications. The results show that a lot of normal faulting type earthquakes concentrate in the central Tibetan plateau. Many of them are nearly perfect normal fault events. The strikes of the fault planes of the normal faulting earthquakes are almost in the N-S direction based on the analyses of the equal area projection diagrams of fault plane solutions. It implies that the dislocation slip vectors of the normal faulting type events have quite great components in the E-W direction. The extension is probably an eastward extensional motion, mainly a tectonic active regime in the altitudes of the plateau. The tensional stress in the E-W or WNW-ESE direction predominates the earthquake occurrence in the normal event region of the central plateau. A number of thrust fault and strike-slip fault type earthquakes with strong compressive stress nearly in the NNE-SSW direction occurred on the edges of the plateau. The eastward extensional motion in the Tibetan plateau is attributable to the eastward movement of materials in the upper mantle based on_seismo-tomographic results. The eastward extensional motion in the Tibetan plateau may be related to the eastward extrusion of hotter mantle materials beneath the east boundary of the plateau. The northward motion of the Tibetan plateau shortened in the N-S direction probably encounters strong obstructions at the western and northern margins. Extensional motions from the relaxation of the topography and/or gravitational collapse in the altitudes of the plateau occur hardly in the N-S direction. The obstruction for the plateau to move eastward is rather weak.

关键词： normal faulting earthquake focal mechanism solution eastward extensional motion stressfield gravitational collapse