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Related papers: Envelope Expansion with Core Collapse. I. Spherica…

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We investigate self-similar magnetohydrodynamic (MHD) processes in an isothermal self-gravitating fluid with a quasi-spherical symmetry and extend the envelope expansion with core collapse (EECC) solutions of Lou & Shen by incorporating a…

Astrophysics · Physics 2009-11-11 Cong Yu , Yu-Qing Lou

We seek for self-similar solutions describing the time-dependent evolution of self-gravity systems with either spherical symmetry or axisymmetric disk geometry. By assuming self-similar variable $x\equiv r/at$ where $a$ is isothermal sound…

Astrophysics · Physics 2014-10-13 Yue Shen , Yu-Qing Lou

We explore MHD solutions for envelope expansions with core collapse (EECC) with isothermal MHD shocks in a quasi-spherical symmetry and outline potential astrophysical applications of such magnetized shock flows. MHD shock solutions are…

Astrophysics · Physics 2009-11-11 Cong Yu , Yu-Qing Lou , Fu-Yan Bian , Yan Wu

We explore self-similar dynamical processes in a spherical isothermal self-gravitational fluid with an emphasis on shocks and outline astrophysical applications of such shock solutions. The previous similarity shock solutions of Tsai & Hsu…

Astrophysics · Physics 2009-11-13 Fu-Yan Bian , Yu-Qing Lou

Self-similar shock solutions in spherically symmetric polytropic gas flows are constructed and analyzed in contexts of proto-star formation processes. Among other possible solutions, we model a similarity shock across the sonic critical…

Astrophysics · Physics 2009-11-11 Yu-Qing Lou , Yang Gao

We present the exact solutions for the collapse of a spherically-symmetric, cold (i.e., pressureless) cloud under its own self-gravity, valid for arbitrary initial density profiles and not restricted to the realm of self-similarity. These…

Astrophysics of Galaxies · Physics 2018-01-08 Eric R. Coughlin

In this paper, we consider the finite-time blowup of hollow vortices. These are solutions of the two-dimensional Euler equations for which the fluid domain is the complement of finitely many Jordan curves $\Gamma_1, \ldots, \Gamma_M$, and…

Analysis of PDEs · Mathematics 2025-06-05 Robin Ming Chen , Samuel Walsh , Miles H. Wheeler

We explore self-similar hydrodynamic evolution of central voids embedded in an isothermal gas of spherical symmetry under the self-gravity. More specifically, we study voids expanding at constant radial speeds in an isothermal gas and…

Solar and Stellar Astrophysics · Physics 2009-08-11 Yu-Qing Lou , Xiang Zhai

We explore semi-complete self-similar solutions for the polytropic gas dynamics involving self-gravity under spherical symmetry, examine behaviours of the sonic critical curve, and present new asymptotic collapse solutions that describe…

Astrophysics · Physics 2009-11-11 Yu-Qing Lou , Wei-Gang Wang

We investigate the Hierarchical Gravitational Fragmentation scenario through numerical simulations of the prestellar stages of the collapse of a marginally gravitationally unstable isothermal sphere immersed in a strongly gravitationally…

Astrophysics of Galaxies · Physics 2015-10-26 Raúl Naranjo-Romero , Enrique Vázquez-Semadeni , Robert M. Loughnane

Critical collapse is a well-studied subject for a variety of self-gravitating matter. One of the most intensively examined models is that of perfect fluids, which have been used extensively to describe compact objects such as stars, as well…

General Relativity and Quantum Cosmology · Physics 2025-09-10 Jorge V. Rocha , Diogo L. F. G. Silva

We propose self-similar shocked flow models for certain dynamical evolution phases of young stellar objects (YSOs), `champagne flows' of H {\sevenrm II} regions surrounding OB stars and shaping processes of planetary nebulae (PNe). We…

Astrophysics · Physics 2009-11-10 Yue Shen , Yu-Qing Lou

We show the existence of a new class of initially smooth spherically symmetric self-similar solutions to the non-isentropic Euler-Poisson system. These solutions exhibit supersonic gravitational implosion in the sense that the density…

Analysis of PDEs · Mathematics 2025-03-18 Christopher Alexander , Mahir Hadžić , Matthew Schrecker

We solve the continuation problem for the non-isentropic Euler equations following the collapse of an imploding shock wave. More precisely, we prove that the self-similar G\"uderley imploding shock solutions for a perfect gas with adiabatic…

Analysis of PDEs · Mathematics 2024-03-20 Juhi Jang , Jiaqi Liu , Matthew Schrecker

We carry out the first main step towards the construction of new examples of complete embedded self-similar surfaces under mean curvature flow. An approximate solution is obtained by taking two known examples of self-similar surfaces and…

Differential Geometry · Mathematics 2010-04-16 Xuan Hien Nguyen

(accepted for publication in the Ap.J.) I present a general classification of self-similar solutions to the equations of gravitational hydrodynamics that contain many previous results as special cases. For cold flows with spherical…

Astrophysics · Physics 2009-10-22 Ue-Li Pen

Similarity solutions are found for the adiabatic collapse of density perturbations $\delta M/M \propto r^{-s}$ $(s>0)$ in a flat universe containing collisional gas only. The solutions are obtained for planar, cylindrical, and spherical…

Astrophysics · Physics 2008-11-26 Leonid Chuzhoy , Adi Nusser

A new self-similar solution describing the dynamical condensation of a radiative gas is investigated under a plane-parallel geometry. The dynamical condensation is caused by thermal instability. The solution is applicable to generic flow…

Astrophysics · Physics 2009-11-13 Kazunari Iwasaki , Toru Tsuribe

Theoretically, stars have been formed from the collapse of cores in the molecular clouds. Historically, the core had been assumed as an singular isothermal sphere (SIS), and the collapse had been investigated by a self-similar manner. This…

Astrophysics of Galaxies · Physics 2015-05-19 Mohsen Nejad-Asghar

We explore the dynamical restrictions on the structure of dark matter halos through a study of cosmological self-similar gravitational collapse solutions. A fluid approach to the collisionless dynamics of dark matter is developed and the…

Astrophysics · Physics 2009-10-31 Kandaswamy Subramanian
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