Related papers: Ice aggregate contacts at the nm-scale
Aggregation of dust through sticking collisions is the first step of planet formation. Basic physical properties of the evolving dust aggregates strongly depend on the porosity of the aggregates, e.g. mechanical strength, thermal…
Many questions in physical cosmology regarding the thermal history of the intergalactic medium, chemical enrichment, reionization, etc. are thought to be intimately related to the nature and evolution of pregalactic structure. In particular…
In laboratory experiments we observe that ice particles (\leq100 \mu m) entrained in a low pressure atmosphere (~1 mbar) get trapped by temperature gradients between three reservoirs at different tempertature. Confining elements are a…
We discuss the results of laboratory measurements and theoretical models concerning the aggregation of dust in protoplanetary disks, as the initial step toward planet formation. Small particles easily stick when they collide and form…
Non-polar magnetic nanoparticles agglomerate upon cooling. This process is followed by in-situ small angle X-ray scattering to assess structural properties of the emerging agglomerates. On the length scale of a few particle diameters, no…
Due to the gas rich environments of early circumstellar disks, the gravitational collapse of cool, dense regions of the disk form fragments largely composed of gas. During formation, disk fragments may attain increased metallicities as they…
Recently, high-resolution Chandra observations revealed the existence of very sharp features in the X-ray surface brightness and temperature maps of several clusters (Vikhlinin et. al., 2001). These features, called ``cold fronts'', are…
Water ice is abundant in protoplanetary disks. Its sticking properties are therefore important during phases of collisional growth. In this work, we study the sticking and rolling of 1.1 mm ice grains at different temperatures. We find a…
An extremely broad and important class of phenomena in nature involves the settling and aggregation of matter under gravitation in fluid systems. Some examples include: sedimenting marine snow particles in lakes and oceans (central to…
The study of the development of structures on multiple scales in the cold interstellar medium has experienced rapid expansion in the past decade, on both the observational and the theoretical front. Spectral line studies at (sub-)millimeter…
Selected results from recent studies of star formation in galaxies at different stages of interaction are reviewed. Recent results from the Spitzer Space Telescope are highlighted. Ideas on how large-scale driving of star formation in…
The interaction of magnetic turbulence and relativistic particles is a important process for understanding particles propagation and acceleration in many astrophysical environments. Large-scale turbulence can be generated in the…
A simple model of irreversible aggregation under differential sedimentation of particles in a fluid is presented. The structure of the aggregates produced by this process is found to feed back on the dynamics in such a way as to stabilise…
The formation and growth of ice particles, particularly on the surfaces of spherical water droplets, bear profound implications for localized weather systems and global climate. Herein, we develop a theoretical framework for ice nucleation…
To reveal the formation of planetesimals it is of great importance to understand the collision behavior of the dusty and icy aggregates they have formed from. We present an experimental setup to investigate the aggregation properties in…
Recent research on the buildup of rocks from small dust grains has reaffirmed that grain growth in protoplanetary disks should occur quickly. Calculation of growth rates have been made for a variety of growth processes and generally predict…
The coagulation of microscopic dust into planetesimals is the first step towards planet formation. The size and shape of the growing aggregates determine the efficiency of this early growth. It has been proposed that fluffy ice aggregates…
Ice-templating is a simple materials processing and shaping route where the growth of crystals from a solvent template the porosity. Although the principles of ice-templating were established a long time ago, it has lured considerable…
We analyze the gravitational collapse of solids subject to gas drag in a protoplanetary disk. We also study the stirring of solids by turbulent fluctuations to determine the velocity dispersion and thickness of the midplane particle layer.…
A method for computing the thermopower in interacting systems is proposed. This approach, which relies on Monte Carlo simulations, is illustrated first for a diatomic chain of hard-point elastically colliding particles and then in the case…