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The isotopic heterogeneity of the Solar System shown by meteorite analyses is more pronounced for its earliest objects, the Calcium-Aluminum-rich Inclusions (CAIs). This suggests that it was inherited from spatial variations in different…

Earth and Planetary Astrophysics · Physics 2019-10-22 Emmanuel Jacquet , Francesco C. Pignatale , Marc Chaussidon , Sébastien Charnoz

Radio continuum observations trace thermal emission of ionized plasma in planetary nebulae and bring useful information on nebular geometries. A model of homogeneous sphere or shell cannot fit the nebular spectra and brightness…

Many chondrules are found to be surrounded by a fine grained rim. Supposedly, these rims were acquired from dust accreted to the chondrules in a protoplanetary disk. In numerical simulations we study the heat transfer in illuminated bare…

Earth and Planetary Astrophysics · Physics 2016-04-12 Christoph Loesche , Gerhard Wurm

A prevailing open problem in planetary nebulae research, and photoionized gaseous nebulae research at large, is the systematic discrepancies in electron temperatures and ionic abundances as derived from recombination and collisionally…

Solar and Stellar Astrophysics · Physics 2018-10-17 Manuel A. Bautista , Ehab E. Ahmed

Meteorite studies have revealed the presence of short-lived radioactivities in the early solar system. The current data suggests that the origin of at least some of the radioactivities requires contribution from recent nucleosynthesis at a…

Astrophysics · Physics 2009-11-07 Harri A. T. Vanhala , Alan P. Boss

We review the evidence for cosmic ray acceleration in the superbubble/hot phase of the interstellar medium, and discuss the implications for the composition of cosmic rays and the structure and evolution of the interstellar medium. We show…

Astrophysics · Physics 2009-10-31 R. E. Lingenfelter , J. C. Higdon , R. Ramaty

We show that a fast wind that expands into a bipolar nebula composed of two opposite jet-inflated bubbles can form a pair of bipolar rings around giant stars. Our model assumes three mass loss episodes: a spherical slow and dense shell, two…

Solar and Stellar Astrophysics · Physics 2016-09-07 Muhammad Akashi , Noam Soker

Extrasolar planets appear in a chemical diversity unseen in our own solar system. Despite their atmospheres being cold, continuous and transient plasma processes do affect these atmosphere where clouds form with great efficiency. Clouds can…

Solar and Stellar Astrophysics · Physics 2018-09-26 Ch. Helling , I. Vorgul

The internal velocity fields of planetary nebulae are studied with a resolution of 5 km s$^{-1}$. We analyze deep echelle spectra from three nebulae in the Bulge, the Sagittarius Dwarf and the SMC. No effects of metallicity is seen, except…

Astrophysics · Physics 2009-11-07 Krzysztof Gesicki , Albert A. Zijlstra

Primitive meteorites are dominated by millimeter-size silicate spherules called chondrules. The nature of the high-temperature events that produced them in the early solar system remains enigmatic. Beside their thermal history, one…

Earth and Planetary Astrophysics · Physics 2015-06-18 Emmanuel Jacquet

Understanding the origin of comets requires knowledge of how the Solar System formed from a cloud of dust and gas 4.567 Gyr ago. Here, a review is presented of how the remnants of this formation process, meteorites and to a lesser extent…

Earth and Planetary Astrophysics · Physics 2025-06-04 Bernard Marty , Katherine R. Bermingham , Larry R. Nittler , Sean N. Raymond

We explore the formation of multipolar structures in planetary and pre-planetary nebulae from the interaction of a fast post-AGB wind with a highly inhomogeneous and filamentary shell structure assumed to form during the final phase of the…

Solar and Stellar Astrophysics · Physics 2015-06-16 W. Steffen , N. Koning , A. Esquivel , G. Garcia-Segura , Ma. T. Garcia-Diaz , J. A. Lopez , M. Magnor

Comet nuclei in the outer Solar system are constantly irradiated by cosmic rays at low temperatures. Accumulated high concentrations of radicals can undergo fast recombination with significant heating of cometary surface layers. We present…

Earth and Planetary Astrophysics · Physics 2023-12-25 D. V. Belousov , A. K. Pavlov

The formation of the toroidal and jet-like structures in the central part of the Crab Nebula is explained in the framework of Kennel & Coroniti theory. The only new element introduced by us in this theory is the initial anisotropy of the…

Astrophysics · Physics 2009-11-07 S. V. Bogovalov , D. V. Khangoulian

We propose a scenario that explains the apparent nitrogen deficiency in comets in a way consistent with the fact that the surfaces of Pluto and Triton are dominated by nitrogen-rich ice. We use a statistical thermodynamic model to…

We propose that interstellar extreme scattering events, usually observed as pulsar scintillations, may be caused by a coherent agent rather than the usually assumed turbulence of $\rm H_2$ clouds. We find that the penetration of a flux of…

Astrophysics of Galaxies · Physics 2013-12-03 M. Angeles Perez-Garcia , Joseph Silk , Ue-Li Pen

It is shown that a generalized magneto-Bernoulli mechanism can effectively generate high velocity flows in the Solar chromosphere by transforming the plasma pressure energy into kinetic energy. It is found that at reasonable heights and for…

An analysis of the OIII and SIII temperatures measurements compiled by Perez-Montero et al. of emission line objects consisting of HII galaxies, giant extragalactic HII regions, Galactic HII regions and HII regions from the Magellanic…

Chandra gratings spectra of a sample of 15 massive OB stars were analyzed under the basic assumption that the X-ray emission is produced in an ensemble of shocks formed in the winds driven by these objects. Shocks develop either as a result…

Astrophysics · Physics 2009-11-13 Svetozar A. Zhekov , Francesco Palla

The solar atmosphere was traditionally represented with a simple one-dimensional model. Over the past few decades, this paradigm shifted for the chromosphere and corona that constitute the outer atmosphere, which is now considered a dynamic…

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