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Related papers: Magnetic Aggregation I: Aggregation Dynamics and N…

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The path to understanding star formation processes begins with the study of the formation of molecular clouds. The outskirts of these clouds are characterized by low column densities that allow the penetration of ultraviolet radiation,…

Astrophysics of Galaxies · Physics 2021-02-24 L. Beitia-Antero , A. I. Gómez de Castro , J. C. Vallejo

Radiative torques on irregular dust grains, in addition to producing superthermal rotation, play a direct dynamical role in the alignment of interstellar dust with the local magnetic field. The equations governing the orientation of…

Astrophysics · Physics 2009-10-28 B. T. Draine , Joseph C. Weingartner

Context: In protoplanetary disks, dust grains coagulate with each other and grow to form aggregates. As these aggregates grow by coagulation, their filling factor \phi decreases down to \phi << 1. However, comets, the remnants of these…

Earth and Planetary Astrophysics · Physics 2015-06-15 Akimasa Kataoka , Hidekazu Tanaka , Satoshi Okuzumi , Koji Wada

Debris discs are often modelled assuming compact dust grains, but more and more evidence for the presence of porous grains is found. We aim at quantifying the systematic errors introduced when modelling debris discs composed of porous dust…

Solar and Stellar Astrophysics · Physics 2016-10-21 Robert Brunngräber , Sebastian Wolf , Florian Kirchschlager , Steve Ertel

In a previous paper we formulated the problem of the formation and evolution of fragments (or cores) in magnetically-supported, self-gravitating molecular clouds in axisymmetric geometry, accounting for the effects of ambipolar diffusion…

Solar and Stellar Astrophysics · Physics 2015-05-18 M. W. Kunz , T. Ch. Mouschovias

Context.Within the sequential accretion scenario of planet formation, planets are build up through a sequence sticking collisions. The outcome of collisions between porous dust aggregates is very important for the growth from very small…

Earth and Planetary Astrophysics · Physics 2016-12-09 Alexander Seizinger , Roland Speith , Wilhelm Kley

Collisional growth of submicron-sized dust grains into macroscopic aggregates is the first step of planet formation in protoplanetary disks. These grains are expected to carry nonzero negative charges in the weakly ionized disks, but its…

Earth and Planetary Astrophysics · Physics 2015-05-20 Satoshi Okuzumi , Hidekazu Tanaka , Taku Takeuchi , Masa-aki Sakagami

We study effect of magnetic field on massive dense core formation in colliding unequal molecular clouds by performing magnetohydrodynamic simulations with sub-parsec resolution (0.015 pc) that can resolve the molecular cores. Initial clouds…

Astrophysics of Galaxies · Physics 2020-07-23 Nirmit Sakre , Asao Habe , Alex R. Pettitt , Takashi Okamoto

We studied experimentally the effect of grain size and maximum load on the compaction and subsequent relaxation of a granular column when it is subjected to vertical uniaxial compression. The experiments were performed using two different…

Soft Condensed Matter · Physics 2021-07-14 Felipe Pacheco-Vázquez , Tomomi Omura , Hiroaki Katsuragi

Interstellar dust grains do not have a single well-defined origin. Stars are demonstrably dust producers, but also efficient destroyers of cosmic dust. Dust destruction in the ISM is believed to be the result of SN shocks hitting the…

Astrophysics of Galaxies · Physics 2016-06-24 Lars Mattsson

We investigate the evolution of magnetic fields in galaxy clusters starting from constant primordial fields using highly resolved ($\approx \rm 4 ~kpc$) cosmological MHD simulations. The magnetic fields in our sample exhibit amplification…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-27 Paola Domínguez-Fernández , Franco Vazza , Marcus Brüggen , Gianfranco Brunetti

The temperature structure of protoplanetary disks provides an important constraint on where in the disks rocky planets like our own form. Recent nonideal magnetohydrodynamical (MHD) simulations have shown that the internal Joule heating…

Earth and Planetary Astrophysics · Physics 2023-06-14 Katsushi Kondo , Satoshi Okuzumi , Shoji Mori

Many technologically useful materials are polycrystals composed of a myriad of small monocrystalline grains separated by grain boundaries. Dynamics of grain boundaries play a crucial role in determining the grain structure and defining the…

Materials Science · Physics 2021-07-07 Katayun Barmak , Anastasia Dunca , Yekaterina Epshteyn , Chun Liu , Masashi Mizuno

We review the present theoretical and numerical understanding of magnetic field amplification in cosmic large-scale structure, on length scales of galaxy clusters and beyond. Structure formation drives compression and turbulence, which…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-28 J. Donnert , F. Vazza , M. Brüggen , J. ZuHone

The early stages of planet formation are still not well understood. Coagulation models have revealed numerous obstacles to the dust growth, such as the bouncing, fragmentation and radial drift barriers. We study the interplay between dust…

Earth and Planetary Astrophysics · Physics 2013-07-24 J. Drazkowska , F. Windmark , C. P. Dullemond

Context: Protoplanetary disks are observed to remain dust-rich for up to several million years. Theoretical modeling, on the other hand, raises several questions. Firstly, dust coagulation occurs so rapidly, that if the small dust grains…

Earth and Planetary Astrophysics · Physics 2009-08-21 T. Birnstiel , C. P. Dullemond , F. Brauer

We perform coagulation and fragmentation simulations using the new physically-motivated model by Garaud et al. (2013) to determine growth locally in brown dwarf disks. We show that large grains can grow and that if brown dwarf disks are…

Earth and Planetary Astrophysics · Physics 2015-06-16 Farzana Meru , Marina Galvagni , Christoph Olczak

Dust clouds influence the atmospheric structure of brown dwarfs, and they affect the heat transfer and change the gas-phase chemistry. However, the physics of their formation and evolution is not well understood. In this letter, we predict…

Astrophysics · Physics 2016-08-30 CH. Helling , W. -F. Thi , P. Woitke , M. Fridlund

The in-situ detection of interstellar dust grains in the Solar System by the dust instruments on-board the Ulysses and Galileo spacecraft as well as the recent measurements of hyperbolic radar meteors give information on the properties of…

Astrophysics · Physics 2015-06-24 M. Landgraf , W. J. Baggaley , E. Grün , H. Krüger , G. Linkert

Supernova ejecta and stellar winds are believed to produce interstellar dust grains with relatively large sizes. Smaller grains can be produced via the shattering of large grains that have been stochastically accelerated. To understand this…

Astrophysics of Galaxies · Physics 2022-12-07 Eric R. Moseley , Romain Teyssier , B. T. Draine