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Related papers: Comparing shocks in planetary nebulae with the sol…

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Non-equilibrium ionization (NEI) is essentially required for astrophysical plasma diagnostics once the plasma status departs from ionization equilibrium assumptions. In this work, we perform fast NEI calculations combined with…

Solar and Stellar Astrophysics · Physics 2023-02-08 Chengcai Shen , John C. Raymond , Nicholas A. Murphy

The formation of chondrules in the protoplanetary nebulae causes many questions concerning the formation process, the source of energy for melting the rims, and the composition of the origin material. The aim of this work is to explore the…

Solar and Stellar Astrophysics · Physics 2013-04-05 H. Joham , E. A. Dorfi

We present a study of the X-ray emission from numerical simulations of hot bubbles in planetary nebulae (PNe). High-resolution, two-dimensional, radiation-hydrodynamical simulations of the formation and evolution of hot bubbles in PNe, with…

Solar and Stellar Astrophysics · Physics 2016-09-21 J. A. Toalá , S. J. Arthur

Several lines of evidence suggest that fine silicate crystals observed in primitive meteorite and interplanetary dust particles (IDPs) nucleated in a supersaturated silicate vapor followed by crystalline growth. We investigated evaporation…

Earth and Planetary Astrophysics · Physics 2015-05-19 H. Miura , K. K. Tanaka , T. Yamamoto , T. Nakamoto , J. Yamada , K. Tsukamoto , J. Nozawa

I review what is known about the temperature of the plasma within stellar wind bubbles and superbubbles. Classical theory suggests that it should be hot, with characteristic temperatures of order a million degrees. This temperature should…

Astrophysics · Physics 2007-05-23 Mordecai-Mark Mac Low

We investigate the evolution of intracluster medium during a cluster merger, explicitly considering the relaxation process between the ions and electrons by N-body and hydrodynamical simulations. When two subclusters collide each other, a…

Astrophysics · Physics 2009-10-31 Motokazu Takizawa

Collisionless shocks are loosely defined as shocks where the transition between pre-and post-shock states happens on a length scale much shorter than the collisional mean free path. In the absence of collision to enforce thermal equilibrium…

Astrophysics of Galaxies · Physics 2015-06-16 Parviz Ghavamian , Steven J. Schwartz , Jeremy Mitchell , Adam Masters , J. Martin Laming

Shocks are a universal feature of the lower solar atmosphere which consists of both ionised and neutral species. Including partial ionisation leads to a finite-width existing for shocks, where the ionised and neutral species decouple and…

Solar and Stellar Astrophysics · Physics 2021-01-20 B. Snow , A. Hillier

In situ observations of the solar wind frequently show the temperature of $\alpha$-particles (fully ionized helium), $T_\alpha$, to significantly differ from that of protons (ionized hydrogen), $T_p$. Many heating processes in the plasma…

We examine mechanisms that may explain the luminosities and relatively low temperatures of extended X-ray emission in planetary nebulae. By building a simple flow structure for the wind from the central star during the proto, and early,…

Astrophysics · Physics 2009-11-07 Noam Soker , Joel H. Kastner

The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal…

Solar and Stellar Astrophysics · Physics 2017-10-11 Steven R. Cranmer , Sarah E. Gibson , Pete Riley

We present first results of three dimensional relativistic magnetohydrodynamical simulations of Pulsar Wind Nebulae. They show that the kink instability and magnetic dissipation inside these nebulae may be the key processes allowing to…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Oliver Porth , Serguei S. Komissarov , Rony Keppens

Planetary nebulae (PNe) are an exciting addition to the zoo of X-ray sources. Recent Chandra and XMM-Newton observations have detected diffuse X-ray emission from shocked fast winds in PN interiors as well as bow-shocks of fast collimated…

Astrophysics · Physics 2007-05-23 M. A. Guerrero , Y. -H. Chu , R. A. Gruendl

Planets, embedded in their natal discs, harbour hot envelopes. When pebbles are accreted by these planets, the contained volatile components may sublimate, enriching the envelope and potentially changing its thermodynamical properties.…

Earth and Planetary Astrophysics · Physics 2023-06-28 Yu Wang , Chris W. Ormel , Pinghui Huang , Rolf Kuiper

Impacts between planetesimals have largely been ruled out as a heat source in the early Solar System, by calculations that show them to be an inefficient heat source and unlikely to cause global heating. However, the long-term, localized…

Earth and Planetary Astrophysics · Physics 2012-08-09 T. M. Davison , F. J. Ciesla , G. S. Collins

The propagation of a shock wave into a medium is expected to heat the material beyond the shock, producing noticeable effects in intensity line ratios such as [O III]/Halpha. To investigate the occurrence of shocks in planetary nebulae…

Solar and Stellar Astrophysics · Physics 2015-06-16 M. A. Guerrero , J. A. Toalá , J. J. Medina , V. Luridiana , L. F. Miranda , A. Riera , P. F. Velázquez

Ambient plasma electrons undergo strong heating in regions associated with compressive traveling interplanetary solar-wind bulk-velocity jumps due to their specific interactions with the jump-inherent electric fields. After thermalization…

Space Physics · Physics 2014-11-19 Hans J. Fahr , Igor V. Chashei , Daniel Verscharen

Using analytic methods and $1$-D two-fluid simulations, we study the effect of cosmic rays (CRs) on the dynamics of interstellar superbubbles (ISBs) driven by multiple supernovae (SNe)/stellar winds in OB associations. In addition to CR…

Astrophysics of Galaxies · Physics 2017-11-08 Siddhartha Gupta , Biman B. Nath , Prateek Sharma , David Eichler

Heat conduction has been found a plausible solution to explain discrepancies between expected and measured temperatures in hot bubbles of planetary nebulae (PNe). While the heat conduction process depends on the chemical composition, to…

Solar and Stellar Astrophysics · Physics 2016-01-27 Christer Sandin , Matthias Steffen , Detlef Schönberner , Ute Rühling

Rapid cooling of planetesimal cores has been inferred for several iron meteorite parent bodies based on metallographic cooling rates, and linked to the loss of their insulating mantles during impacts. However, the timing of these disruptive…

Earth and Planetary Astrophysics · Physics 2022-11-16 Alison C. Hunt , Karen J. Theis , Mark Rehkämper , Gretchen K. Benedix , Rasmus Andreasen , Maria Schönbächler